2000 stereochemistry

stereochemistry (general, optical resolution)O 0030

30 - 039A Convenient Route to Enantiomerically Pure Highly OxygenatedDecalins from Sugar Allyltin Derivatives. — Chiral dienoaldehydesof type (I), recently prepared from sugar allyltins, are the precursors for thetitle compounds, which are prepared via phosphonates (IV), (VII), and (IX)by a tandem Wittig type Diels–Alder reaction with aldehydes such as (V) and(XIV) to give cis-decalins in a highly stereoselective manner [products (XI)–(XIII) obtained in the same way]. Besides phosphonates, the correspondingphosphoranes, also available from the starting dienoaldehydes, can be alsoapplied in this reaction affording the decalins with the same stereochemicaloutcome but with significantly lower yields. The stereochemistry of the tandemWittig type Diels–Alder reaction depends solely on the geometry of the startingphosphonates (or corresponding phosphoranes) when they derived from D-lyxo-or L-arabino sugars, e.g. compounds (VII) and (IX). In the case of D-xylo-phosphorus compounds such as (IV), the configuration of the products dependson the used aldehyde. — (JAROSZ, SLAWOMIR; SKORA, STANISLAW;Tetrahedron: Asymmetry 11 (2000) 6, 1433-1448; Inst. Org. Chem., Pol. Acad.Sci., PL-01-224 Warszawa, Pol.; EN)

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2000 stereochemistry

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