2 Pentaco-ordinated and Hexaco-ordinated Compounds

BY C. D. HALL

1.1- - Interest in hypervalent phosphorus chemistry has been maintained throughout the year but the emphasis in this arena is now clearly towards the study of mono-, bi- and polycyclic structures. The section on structure, bonding and ligand reorganisation in hypervalent phosphorus species is no longer justifiable in its own right and these topics have been incorporated into the later sections. Theoretical studies on the role of pentaco-ordinate phosphorus in transphosphorylation reactions have, however, generated considerable interest. For example, Lim and Tole have modelled the transphosphorylation step in RNaseA catalysis by ab-initio M.O. calculations on the free energy profde for the dissociation of HOC2H40P(O)(OMe)O- (MEW) to

C2HqP04- (EP) and methano1.l The gas phase reaction was computed to proceed via a stepwise mechanism involving a monoanionic pentacovalent intermediate (I-GN) which had to rotate about an equatorial P-OH bond to yield a phosphorane monoanion in a conformation (I-$) activated

for exocyclic cleavage (Scheme 1). Taka2 and Karplus3 have also reported that monoanionic species (but not dianionic species) can be located as stable intermediates on the potential surface of the gas-phase reaction. Subsequently Taira arrived at the conclusion, based on his theoretical calculations, that in aqueous solution when species are sufficiently hydrated, any pentacoordinate oxyphosphorane including those present as dianionic species, can exist as an intermediate4 Thus, according to Taira, the lack of l80 exchange and the lack of phosphoryl migration observed under basic conditions5v6 should be ascribed to a high energy barrier facing pseudorotation rather than supportive evidence for the non-existence of pentacoordinate intermediates. It is evident from this work that the theoretical approach is becoming more sophisticated and consequently of much greater significance.

2. -s - Attempts to prepare complexes between phosphines (la-d) and mercuric fluoride (2) resulted in oxidative transfer of fluorine to form difluorophosphoranes (3a-d).7 In an attempt to synthesise six-coordinate ions, RPC15-, with sterically hindered R groups, several aryl phosphoranes (5) with bulky ortho substituents were prepared by chlorination of the corresponding phosphines (4) and characterised by 31P nmr and also in some cases by 35Cl NQR spectroscopy. All the compounds had pseudorotational tbp structures which slowly disproportionated back to (4) and the trichloride ion on treatment with chloride. An interesting result was obtained with Ar2PC1 [6, Ar = 2,4,6-(CF3)3 CsHz)] which on treatment with the C12 led to cleavage of the P-C bond with the formation of ArFCl4 and ArC1.8

Pentafluorophenoxytetrachlorophosphorane (7) takes up four molecules of chloral successively to form a penta-alkoxy phosphorane (1 1) via intermediates (8-10) which were detected by l P n ~ n r . ~ A similar series of reactions occurred with bis-(pentafluorophen0xy)- trichlorophosphorane (12) to form the pentaoxyphosphorane (13). In a related reaction, tris-

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64 Organophosphorus Chemistry

OMe OMe Me0

(MHEP)- (E P)- MeoH Free energy gas-phase profile for (MHEP)- -+ (EP)-+ (OH)-. All structures are fully optimized at the HF/3-21 + G* level. The numbers are gas-phase free energies in kcal mol-'

Scheme 1

R3PF2 + Hgo - R3P + HgF2

(1a-d) (2) (3a-d) a, R = Me; b, R = Et C, R = Bun; d, R = Ph

RPC12 + Cl2 - RPC14 RPCI2 + C13-

(4) (5) (4)

Ar2PCI + 2CI2 c ArPCI4 + ArCl

(6) (5, R = Ar)

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2: Pentaco-ordinated and Hexaco-ordinared Compounds 65

C13CCHO

C13CCHO

3CI3CHO - 2C13CCHO -

Y \

(16a,b) a, X,Y = Br b, X = Br; Y = CI

Co + 2Me3P12 - [Co(PMe3)213] + ’12 I2

(1 7)

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66 Organophosphorus Chemistry

(2,2,2-trifluoroethoxy)dicyanophosphorane (14) was shown to react with chloral to form the pentaalkoxyphosphorane (15). lo Kozlov et al. have reported' that the 35Cl NQR spectra of the trichlorophosphoranes (1 6ab) contain two lines in the 28 MHz region and not one as previously published.12 This led to a representation of the structures of the molecule as tbp's with tri- haloaryloxy groups in equatorial positions.

In a continuation of studies on the reaction of coarse-grain metal powders with phosphoranes, McAuliffe et al. describe the reactions of cobalt powder with trialkyldi- iodophosphoranes (R3P12). l3 With R=Me, the reaction proceeds to form (17) which was shown

by X-ray crystallography to be one of the rare examples of tbp Co3+ complexes containing tertiary phosphine ligands, thus emphasising the synthetic utility of dihalophosphorane structures.

3. Monocyclic Phosphoranes - Diethyl(trichloromethy1)phosphine (1 8) reacts via (19) with methyl isocyanate (20) and with non-enolisable aldehydes (21a-d) to produce l ,2-h5- oxaphosphetanes (22) and (23a-d) respectively. Furthermore, with enolisable saturated ketones (24ab) the reaction proceeds to give cycloaddition products (25ab).14 In a paper devoted to the chemistry of silylcarbodi-imidofluorophosphoranes, Schmutzler and Gruber report that the reaction of (26) with o-chloranil (27) gives the fluorophosphorane (28) which decomposes in solution with formation of Me3SiF.15

An extension of earlier studies (by Gloede and by Denney) on the chlorination of aryl phosphites reveals that the chlorination of chlorodi-aryl phosphites (29a) or dichloroaryl phosphites (29b) gives phosphonium salts (31ab) with unsubstituted aryl groups but phosphoranes (30ab) with o-substituted aryl groups. l6 In a related study of the reaction of sulphenyl chlorides with aromatic phosphites, Gloede also reports that the reaction of (32) with (33) gives (34) which reacts with more (33) to form (35) which in turn disproportionates with another mole of (32) to form (36) and (37).17 The work serves to emphasise the facile ligand exchange which can occur around pentaco-ordinate phosphorus, especially when electronegative ligands which are good leaving groups are involved.

Heating two moles of methyl phenylglyoxylate (39) with tris-2,2,2-trifluoroethyl phosphite (38) at 7OoC for lh gives the dioxaphospholane (40).l8 The reaction of trimethyl phosphite (41) with 2-trifluoroacetylphenol(42) gave (45) via (43) and (44) and the phosphorane was then reduced by (41) to the stable product (46).19 Similar chemistry also generated a number of bicyclic and tricyclic phosphoranes (e.g.47) reported in a poster by Roschenthaler et al. at the 1992 Conference on Phosphorus Chemistry in Toulouse.20

The synthetic utility of pentacovalent phosphorus compounds has been exploited further in the production of phosphonates from the reaction of trialkyl phosphites (48) with methyl vinyl ketone (49) to form (50) which then condenses with a variety of electrophiles (51) to form the highly substituted phosphonates (52) and (53).2 Reaction of the tris-(2,2,2- trifluoroethyl) phosphite (38) with diols containing methylene or sulphur atom bridges produced the new pentaoxyphosphoranes (54-56) containing eight-membered rings. The X-ray crystal structures of (54) and (55) reveal tbp configurations with the ring system apical-equatorial in (54) but di-equatorial in (55). The geometry in (55) was described as " distorted octahedron" with a P-S distance of 2.50481 compared to the sum of the covalent radii at 2.1481 indicating a weakened but significant bond.22 The formation of a pseudo-octahedral structure for (56) was ascribed, at least in part, to the presence of the t-butyl groups relative to the less bulky methyl groups in (55) which together with the two apical trifluoroethoxy groups promote the diequatorial ring

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2: Pentaco-ordinated and Hexaco-ordinuted Compounds 67

MeNCO 7 (21 a-d) 7

O y N M e I Et2P-CC12

I

0 - p I Et,P-CCI,

I CI (23a-d)

a, R=Ph; b, R=pN02C6H4 c, R =CC13; d, R = CMe3

6 31P(253K) = -48.2 ’ J(PF) = 868Hz

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68 0 rganop h osph o rus Chemistry

Ph + I

(CF3CH 20)3P-7-0- C02Me

+ (ArO),PCls, "2 (ArO), PCI5, (29a) Or (29b) (ArO),,." PCI, PCI6.

-

(29a,b) a, n = 2 b, n = l

(30a,b) (31a,b) a, n = O b, n = l

(CF3CH20)3P + PhCOC02Me

(38) (39)

r 1

Ph

(CF3CH20)3& 0-CP h I

C02Me

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2: Pentaco-ordinated and Hexaco-ordinated Compounds 69

(MeO)3P + p C F 3

R

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70 Organophosphorus Chemistry

(48) R = Me, Et, Pr' (49)

/- H

I n v r iw

(51) /

H O= P (OR) 2

\ Pr', Ph, CMe= CH2

y o H U

(54)

I ,

O=P(OR),

(53)

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2: Pentaco-ordinated and Hexaco-ordinated Compounds 71

configuration in (55) . The influence of phosphorus-sulphur bonding in the formation of octahedrally co-ordinated pentaoxyphosphoranes has been explored further by the synthesis and X-ray crystallographic study of three more phosphoranes (57 a-e) containing sulphur in bridged, eight-membered rings . All three showed phosphorus-sulphur co-ordination to various degrees with P-S bond distances of 2.640, 2.744 and 2.88081 for (57a), (57b) and (57c) respectively with the increase along the series attributed to a decrease of electron donation by the akyl groups with Bu > Me. The l H and 31P solution state nmr data are also reported for these compounds.

The syntheses of monocyclic (58,59) and bicyclic (60,6 1) pentaoxyphosphoranes containing 7-membered rings have also been reported.24 X-ray crystallography studies of (58) and (60) revealed tbp structures with the 7-membered rings positioned a-e despite the preference of the electronegative tnfluoroethoxy groups for apical positions and the steric inducement of t-butyl substituents to orientate the rings di-equatorial. The 'H, 19F and 31P nmr data were consistent with the retention of the solid state structures in solution with rapid ligand exchange (pseudorotation) in (58) over the temperature range of +67 to -49OC.

4. Bicvclic and Tricvclic Phosphoranes - A series of phosphoranes (62-65) has been prepared and characterised by 'H nmr andor X-ray crystallography. In the crystalline state compounds (62-64) feature five-coordinate phosphorus within a distorted tbp and with the six-membered ring diequatorial and in the chair conformation. The'H nmr coupling constants revealed that a chair- form ring rather than a boat-twist conformation was populated in solution for all four phosphoranes and that in solution, the six-membered ring of (62) is primarily (90%) in conformation (62a). The trans-fused ring structures of (63-65) are closely related to previously reported phosphoranes (eg 66) prepared as transition state analogues for the hydrolysis of CAMP but the results of this paper "render highly unlikely the assertion that the thymidine-based phosphorane (66) populates in solution, measurable amounts of a permutational isomer with its ring attached to phosphorus in a diequatorial fashion".26

Ligand exchange in cyclic pentaco-ordinate phosphorus chlorides has been demonstrated by the reaction of (67) with PCl3 in nitromethane to form (68) which in turn reacts

with a second mole of (67) to form (69) in quantitative yield.27 The hydridospirophosphorane (70) reacts with enamine (71) to form a-aminoalkylspirophosphoranes (72). On the other hand, with the enamine (73) derived from cyclohexanone, a slow oxidation-reduction process occurs to give the bis-spirophosphorane (74) and the bis-phosphite (75).28 The cyclic phosphite (75) and its silicon analogue (76) can also be converted into aminoakylspirophosphoranes (80) via (78) or (79) by reaction with alkoxymethylamines (77).29

Salicyl phosphites (81) contain a mobile anhydride fragment and reaction with methyl trifluoropyruvate (82) at -4OOC (in ether or CH2Cl2) gives the spirophosphorane (83).30 At

higher temperatures (20-80°C) the 1,3,2,-dioxaphosphepate (84) is formed in varying amounts dependent upon the group, R. Variable temperature nmr studies showed that all three chiral, pentaco-ordinate dioxaphospholenes (85-87) derived from ephedrine were pseudorotationally stable below 6OoC. The AGS values for (85) and (86) were determined to be 22f2 kcal mol-' and 3352.6 kcal mol-l respectively, the latter being the largest quoted to date. Furthermore l H nmr NOE studies on the major isomer of (85,=90% at 2OoC) confirmed that it was (85a) rather than (85b) and conformational analysis of the 'H nmr data indicated a twist-envelope conformation for the ephedrine ring.31

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72 Organophosphorus Chemistry

0Ph

(57a-c) a, R' = R~ = BU'

b, R' = But; R2 = Me c, R' = R2 = Me

. -0C HZCF3 0-P=

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2: Pentaco-ordinated and Hexaco-ordinated Compounds 73

(63) (64)

CF3 CI

(66) R=CH3 R = CHZCH20CH3

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74 Organophosphorus Chemistry

CI

pJ>l + PC15 ao;JtJ-J ' 0 0

H

RCH~CH-N o W

(70) (71) R = Me, Et or Pr (72)

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2: Pentaco-ordinated and Hexaco-ordinated Compounds 75

(76) (79)

+ t

CF3C0.C02Me

+ 0

G L - O R

C02Me 0 CF3

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76 Organophosphorus Chemistry

Triethylammonium salts of unusual a-phosphoranyl-a-hydroxy-acids have been prepared by reacting hydridophosphoranes (88) or (90) with pyruvic (89), phenylpyruvic (89b) or 2-ketoglutaric (89c) acids to form the corresponding hydroxyphosphoranes (91a-c) or (92a-c). After 2-4 days (92a-c) rearranged to mixtures of (93a-c) or (94a-c) and all the structures were confirmed by 13C and l H nmr together with elemental analysis.32 The reaction of phenylchlorophosphine (95) with 5-bromo-N-(carboxymethyl)-anthranilic acid (96) gives an equilibrium mixture of the phosphorane (97) and two tri-coordinate tautomers (98) and (99)33 With 2,2'-iminodibenzoic acid (loo), however, only tricoordinate species - (101) in DMF, or (102) in toluene, were observed.

The oxidation of (103) by CCl4 in the presence of Et3N and a nucleophile (the Atherton-Todd reaction) gave new symmetric (104) and non-symmetric (105a-c) bicyclic p h ~ s p h o r a n e s . ~ ~ The same reaction when performed with a bicyclic phosphorane (e.g. 106) led to a ten-membered ring (107). This work clearly prompted the idea of constructing macrocycles containing bicyclic phosphoranes which could simultaneously recognise both cations (e.g. ammonium ions) by the macrocycle and anions (captured as hexaco-ordinate phosphorus). A typical synthetic scheme involves the formation of (1 10ab) from (108) and (109ab) followed by an Atherton-Todd reaction to give the desired macrocycle (1 1 lab).35 Although the reaction of (1 10ab) proceeds in quantitative yield, the Atherton-Todd cyclisation gave mixtures containing (1 1 lab) and compounds such as (1 12ab) and (1 13ab). The required compounds were isolated in pure form by chromatography on silica gel but the yields were very poor for X=O (=I%) and modest for X=NBu (=14%) These, however, are the first stable macrocyclic compounds with 16 or more atoms containing pentacovalent phosphorus.

In a paper dealing with the chemistry of diaza-2-phosphetidine-4-thione (1 16) derived from N,N'-dimethylthiourea (1 14) and the appropriate aminophosphine (1 15), Schmutzler et al. describe the formation of a variety of pentaco-ordinate species. For example, the reaction of (116ab) with o-chloranil (117) gave (118ab) characterised by mass spectrometry,lH, 13C and

P nmr and for the case of (1 18a) by X-ray crystallography which revealed sqp geometry around p h o ~ p h o r u s . ~ ~

Oxidative reactions of the cyclic phosphoramidite (1 19) with o-chloranil and hexafluoroacetone also led to pentaco-ordinate structures (120) and (121) respectively and X-ray crystallography of (121) revealed a distorted tbp configuration with both rings a-e and the six- membered ring in an envelope conformation with the phosphorus atom out of the plane.37 The formation of pentaco-ordinate phosphorus compounds from iminophosphoranes continues to attract attention. For example, the reaction of (122) with the alcohol (123) gave the monocyclic phosphorane (124) and not the anticipated d i ~ n e r . ~ ~

The reactions of 1,3,2-benzoxazaphospholene (125) with alcohols, phenols and glycols proceed with the cleavage of the exocyclic P-N bond to form (126) followed by N-P migration of the alkyl group to form (127) and then the series of dimeric phosphoranes ( 1 2 ~ ~ ~ The reactions of the amidophosphite (129) with the phosphorane (130) gave, via (13 1). the a i d e (132) which decomposed to (133) and the intermediate (134) which dimerised to ( 135h40 In a similar vein, the cyclic phosphite (136) undergoes the Staudinger reaction with phenyl azide to form the intermediate (137) which dimerises to (138).41 The dimerisation of iminophosphoranes (141) to (142) also features in the reaction of (139) with tetraphenylcyclopentadienone(140)42 The 1O-P- 4 phosphoranide anion (143) coordinates to a large number of metal species to form compounds such as (144) or (145) and likewise (143) reacts with (146) to form ( 147).43

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2: Pentaco-ordinated and Hexaco-ordinated Compounds 77

(85-87) (a) (85-87) (b)

(85) R = Me, Ar = Ph (86) R = Ph, Ar = Ph (87) R = Me, Ar = p -MeOC6H4

Me

+ R'CH2COC02H R3N'CH2C'2b

(89a-c) a, R'= H;

+ 0 b, R'= Phi C, R' = CH2C02-NHEt3

0

(88) (91 a-c)

+ (89a-c)

0

0-

0

(92a-c)

0

(93a-c) (94a-c)

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78 Organophosphorus Chemistry

HN_/C02H

+co2H

PhPC12 +

Br

(95)

THF/Et3N

0

(97) 63'P = -57

0

Br

(99) 631P = 146.4

HO?'

Ph-P-N

Br

PhPC12 + Ho2cD HN

H02C

Ph-P-N

0 'a I

0

(98) S3'P = 156

0

Ph

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2: Pentaco-ordinated and Hexaco-ordinated Compounds

CC14 + 2EtaN + NuH 0 ... OMe N -P',

(104) Nu=OMe (1 05a-c)

a, NU = OBU'; b, NU = NEt2; C, Nu=HNPf

/, 0 , n/ M;c? 1,0 NHMe .O N..

2 N-P, CC14/Et3N t N-P, ;P-N in CH3CN

79

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80 Organophosphorus Chemistry

?P + HOnXnOH -

(1 08) (1 09a,b)

a, X = O b, X = NBu"

(1 12a,b)

( 1 1 Oa, b)

(109a) or (109b) I

( 1 1 1 a, b)

(113a,b)

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2: Pentaco-ordinated and Hexaco-ordinated Compounds 81

S

MeNHK NHMe

Me

Bu"Li

MeN\P/N Me + C12PNR2

I NR2

(1 15a,b)

a, R = C6HI1 b, R = P h

(1 16a,b)

Me (1 18a,b)

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82 Organophosphorus Chemistry

ROH (-Et2N H)

v

(126) R = Ph, 2,4-CI2C6H3 or Pr’ (1 27)

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2: Penraco-ordinated and Hexaco-ordinuted Compounds

CF3 (Et0)ZPNHPh + Y O ‘ PC 13

N .N’ I Ph

r

Ph L

I CI Ph

(1 32)

83

Ph

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84 Organophosphorus Chemistry

Ph I

---s--+ O N 0

I Ph

Ph Ph

Ph q P h

0

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2: Pentaco-ordinated and Hexaco-ordinated Compounds 85

co

F3C CF3 F3C CF3

BrAuPEt3 ___)

F3C CF3

co

co F3C CF3

(1 52a, b) b, R = Me0

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86 Organophosphorus Chemistry

Some very interesting work has appeared on the use of the bicyclic aminophosphine (148) as an extremely efficient catalyst for the trimerisation of aryl isocyanates (149ab) via intermediate (150ab)-(152ab) to form the isocyanurates ( 153ab).44 The unusual basicity of (148) has been discussed in terms of the transannular interaction of the bridgehead nitrogen in (154) and the gradual increase of the P - N u distance from the bonded value of 1.967A in (154) to 3.33A in

(161) which is close to the sum of the van der Waals radii (3.34A).45

5 . Hexaco-ordinate Phosphorus Compounds- The oxidation of cisltrans-1,5-diaza-2,4- diphosphorinan-6-one (162) with o-chloranil leads to the unusual zwitterionic compound (163) containing two phosphorus atoms of opposite charge and different (h4P+ and h6P-) coordination number.46 The paper also describes some alternative reactions of similar heterocyclic systems leading to hexaco-ordinate products.

In a poster presented to the Toulouse conference, Skowronska et al. described the preparation and stereochemistry of six-coordinate phosphorus compounds formed by the interaction of cyclic phosphoranes with a variety of nucleophiles and examined by a combination of X-ray crystallography, 'H,I9F and l P nmr s p e c t r o s ~ o p y . ~ ~ l n e t i c data derived from the study provided evidence for the intramolecular dissociative mechanism with heterolysis of one of the P -0 endocyclic bonds in the isomerisation of trans-(CgH402)2P-(OAr l)(0Ar2) Et3NH+ into its cis-isomer.

Finally, in a thought-provoking paper, Zhao et al. show that stable amino acids become very reactive when converted into N-phosphorylated derivatives (164) which may then be dimerised to (165), esterified to (166) or trans-esterified at phosphorus to form (167). The authors suggest that these reactions proceed through intramolecular phosphoryl-carboxyl mixed anhydride intermediates of type (168) which fit the active sites of enzymes when the conformation of the intermediate is correct48 Hexaco-ordinate intermediates are also implicated and the authors conclude that "phosphoryl group participation .... is the key to the chemistry of life", a statement which probably comes as no surprise to many of us! D

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2: Pentaco-ordinated and Hexuco-ordinutd Cornpourids 87

(154) H (1 55) PhN=C’-SMe (1 56) MeS( S)C’ (157) S2C (1 58) C12Hg

(1 54) (159) s (1 60) cis -Br(OC)4Re (1 6 1 ) trans -CI2Pt

(R0)2P(0)NHCHMeC02H * (R0)2P(0)NHCHMeC02R’

(1 66)

(RO)(R’O)P(O)NHCH MeC02H

(1 64)

(1 67)

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88 Organophosphorus Chemistry

REFERENCES

1. 2. 3.

4. 5.

6, 7.

8. 9.

10.

11.

12.

13.

14. 15. 16. 17. 18.

19.

20. 21. 22. 23.

24. 25. 26. 27.

28.

29.

30.

31. 32. 33. 34.

C. Lim and P. Tole, J.Am.Chem.Soc., 1992, 114, 7245.

M. Uebayassi, T.Uchimaru. K.Taira, ChemExpress, 1992,7,617. a) C. Lim and M. Karplus, J.Am..Chem.Soc.,1990,112, 5872. b) A. Dejaegere, C.Lim and M. Karplus, J.Am.Chem.Soc., 1991,113, 4353. A.Yliniemela, T.Uchimaru, K. Tanabe and K. Taira, J.Am.Chem.Soc., 1993,115, 3032.

P.C. Haaake and F.H. Westheimer, J.Am. Chem.Soc., 1961, 83.1 102. E.Anslyn and R.Breslow. J.Am.Chem.Soc., 1989,111,4473. K.M. Doxsee, E.M. Hanawalt and T.J.R. Weakley, Inorg.Chem.,1992.31,4420.

K.B. Dillon, T.A. Straw and R.D. Chambers, Phosphorus, Sulfur and Silicon, 1993, 76, 83.

V.F. Mironov, I.V. Konovalova, E.N.Ofitserov and E.1. Goldfarb,

J.Gen.Chem.Engl.transl., 1992, 62 (10) 1840. V.F. Mironov, I.V. Konovalova, E.N. Ofitserov and A.N. Pudovik,

J.Gen. Chem. Engl.transl., 1992.62 (7) 1368.

E.S. Kozlov, 1.A.Kyuntsel' and G.B. Soifer, J.Gen.Chem., Engf.trunsl., 1991, 61 (8) 1763. E.S. Kozlov, N.P. Kolesnik, L.G. Dubenko and M.I. Povolotskii, J.Gen.Chem., USSR, 1979, 49, (4) 769. C.A. McAuliffe, S.M.Godfrey, A.G. Mackie and R.G. Pritchard. Angew.Chem.,Int.Ed.Engl., 1992, 31 (7) 919. P. Majewski, Phosphorus, Sulfur and Silicon, 1992, 71, 59. M. Gruberand R. Schmutzler, Phosphorus, Sulfur and Silicon, 1992,70, 113. J. Gloede, Phosphorus, Sulfur and Silicon, 1993,75, 217, J.Gloede and G.Lutze, Phosphorus, Sulfur and Silicon, 1993,78, 265. I.V. Konovalova, L.A. Burnaeva , I.V. Loginova and A.N. Pudovik, J.Gen.Chem.. EngLtransl., 1991, 61, 2298. R.-D.Hund and G-V.Roschenthaler. Phosphorus, Sulfur and Silicon, 1992,73,99.

R.-D.Hund, G. Bekiaris and G-V. Roschenthaler, Phosphorus, Sulfur and Silicon, 1993.77. 147. C.K. McClure, K-Y Jung, C.W. Grote and K. Hansen, Phosphorus. Sulfur and Silicon, 1993, 75, R.R. Holmes, T.K. Prakasha and R.O. Day, Phosphorus, Sulfur and Silicon, 1993, 75, 249.

T.K. Prakasha, R.O. Day and R.R. Holmes, J.Am.Chem.Soc., 1993, 115, 2690.

T.K. Prakasha, S.D. Burton, R.O. Day and R.R. Holmes, Inorg.Chem., 1992.31, 5494. Y. Huang, A.E. Sopchik, A.M. Arif and W.G. Bentrude. J.Am.Chem.Soc., 1993,115,4031. N.L.H.L. Broeders, K.H. Kook and H.M. Buck, J.AmChem.Soc., 1990, 112, 7475. B.V. Timokhin. V.K. Dimitriev and M.V. Kazantseva. J.Gen.Chem., Engl.transl., 1992,62 (I I ) 2063. A.A. Prishchenko, D.A. Pisamitskii, M.V. Livantsov and V.S. Petrosyan, J.Gen.Chem., Engf.transl., 1992.62, (09) 1772. A.A. Prishchenko, D.A. Pisamiiskii, M.V. Livantsov and V.S. Petrosyan, J.Gen.Chem., Engl.rrunsl., 1992, 62 (09) 1774.

V.F. Mironov, L.A. Burnaeva, V.M. Krokhalev, V.I.Saloutin, I.V. Konvalova, R.A. Mavleev. and P.P. Chernov, J.Gen.Chem., Engl.transl., 1992,62 (06) 1172. C.K. McClure, C.W. Grote and B.A. Lockeit, J.Urg,Chem.,1992, 57, 5195. A. Munoz and L. Iamande, Phosphorus,Sulfur and Silicon, 1992,70, 263. L. Lamande and A. Munoz, PhosphorusJulfur and Silicon, 1993,75, 241. D. Houalla, Z. Bounja, S. Skouta, L. Riesel and D. Lindemann, Phosphorus, SulJur and Silicon, 1993, 77, 216.

Dow

nloa

ded

by Y

ale

Uni

vers

ity o

n 05

Mar

ch 2

013

Publ

ishe

d on

31

Oct

ober

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39/9

7818

4755

4451

-000

63

View Online

2: Pentaco-ordinated and Hexaco-ordinuted Compounds 89

35.

36.

37. 38.

39. 40. 41.

42.

43.

44. 45. 46. 47.

48.

D. Houalla, Z. Bounja, S. Skouta, M. Sanchez and R. Wolf, Phosphorus, Sulfur and Silicon, 1993, 75, 71. M. Furkens, P.G. Jones, A. Fischer and R. Schmutzler, Phosphorus, Sulfur and Silicon, 1992, 73, 195. I.Neda, A.Fischer, P.G.Jones and R. Schmutzler, Phosphorus, Sulfur and Silicon,1993, 78, 271. Yu.G. Shermolovich, V.Yu Abramov, and L.N.Markovskii, J.Gen.Chem.,Engl.transl., 1991, 61, 1588. M.A. Pudovik, S.A. Terent'eva, and A.N. Pudovik, J.Gen.Chem.. Engl.transl., 1992,62 (02) 224. S.K. Tupchienko, T.N. Dudchenko and A.D. Sinitsa, J.Gen.Chem.. EngLtransl., 992,62 (04) 780. V.F. Mironov, R.A .Mavleev, E.N. Ofitserov, I.V. Konovalova, and A.N. Pudovik,

J.Gen.Chem.,Engl.frans1.,1992, 62, 970. A.V. Fuzhenkova, M.I. Tyryshkin and S.A. Terent'eva, J.Gen. Chem.,Engl.transl., 1992, 62 (09) 1771. J.C. Martin, S.R. Chopra, C.D. Moon and T.R. Forbas jr.,Phosphorus, Sulfur and Silicon, 1993, 76, 87. J.-S. Tang and J.G. Verkade, Angew.Chem.lnt.Ed.Eng1.. 1993.32 (6) 896. J-S. Tang, M.A.H. Laramay and J.G. Verkade, Phosphorus, Sulfur and Silicon, 1993,75, 2205. I.V. Shevchenko and R. Schmutzler, Phosphorus, Sulfur and Silicon, 1993,75,233. R. Kaminski, J. LKowara, A. Skowmska, M. Wieczorek, and G. Bujacz, Phosphorus, Sulfir and

Silicon, 1993, 77, 217. Y.-M. Li, Y.-Wu Yin, Y.C. Li, B. Tan, Y. Chen, and Y,-F. Zhao, Phosphorus, Sulfur and Silicon, 1993, 76, 103.

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