cheminform abstract: synthesis and diels—alder reactions of prop-1-ene-1,3-sultone, and chemical...

1999 oxathiole derivatives oxathiole derivatives R 0250 28 - 160 Synthesis and Diels–Alder Reactions of Prop-1-ene-1,3-sultone, and Chemical Transformations of the Diels–Alder Adducts. — A reliable ﬁve-step route for the synthesis of sultone (V) with an overall yield of 34% is presented. The unsaturated sultone (V) is applied as new dienophile in Diels–Alder reactions with a variety of cyclic and acyclic dienes. Good to excellent yields of cycloadducts are obtained in all cases. With dienes (VIb) and (XXII) endo diastereomers are formed exclusively. Unsymmetrical dimers give mixtures of regioisomeric adducts with poor selectivity ranging from 1:1 to 1:5. Tricyclic sultone (VIIa) and bicyclic sultone (XIX) are chosen as model substrates to study the ring opening reactions with nucleophiles like thiolate (IX) and amine (XI). The internal ammonium sulfonates obtained with amine (XI) are derivatized to sultams (XII) and (XXI) for characterization.The alkyla- tion/desulfurization of compound (VIIa) to give methylene derivative (XVII) is successfully achieved by applying optimized conditions (temperature, amounts of BuLi and silane) for the synthesis of the desired alkylated intermediate (XV). — (JIANG, LA SHENG; CHAN, WING HONG; LEE, ALBERT W. M.; Tetrahedron 55 (1999) 8, 2245-2262; Dep. Chem., Hong Kong Baptist Univ., Kowloon, Hong Kong, Peop. Rep. China; EN) 1

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Page 1: ChemInform Abstract: Synthesis and Diels—Alder Reactions of Prop-1-ene-1,3-sultone, and Chemical Transformations of the Diels—Alder Adducts

1999 oxathiole derivatives

oxathiole derivativesR 0250

28 - 160Synthesis and Diels–Alder Reactions of Prop-1-ene-1,3-sultone, andChemical Transformations of the Diels–Alder Adducts. — Areliable five-step route for the synthesis of sultone (V) with an overall yield of34% is presented. The unsaturated sultone (V) is applied as new dienophilein Diels–Alder reactions with a variety of cyclic and acyclic dienes. Good toexcellent yields of cycloadducts are obtained in all cases. With dienes (VIb)and (XXII) endo diastereomers are formed exclusively. Unsymmetrical dimersgive mixtures of regioisomeric adducts with poor selectivity ranging from 1:1to 1:5. Tricyclic sultone (VIIa) and bicyclic sultone (XIX) are chosen as modelsubstrates to study the ring opening reactions with nucleophiles like thiolate(IX) and amine (XI). The internal ammonium sulfonates obtained with amine(XI) are derivatized to sultams (XII) and (XXI) for characterization.The alkyla-tion/desulfurization of compound (VIIa) to give methylene derivative (XVII) issuccessfully achieved by applying optimized conditions (temperature, amountsof BuLi and silane) for the synthesis of the desired alkylated intermediate(XV). — (JIANG, LA SHENG; CHAN, WING HONG; LEE, ALBERT W.M.; Tetrahedron 55 (1999) 8, 2245-2262; Dep. Chem., Hong Kong BaptistUniv., Kowloon, Hong Kong, Peop. Rep. China; EN)