Reversal of Stereoselectivity in [5 + 2] Pyrone−Alkene Cycloadditions Using a Sulfoxide-to-Sulfoximine Switch. Enantiodivergent Synthesis of 8-Oxabicyclo[3.2.1]octane Systems
作者:Fernando López、Luis Castedo、José L. Mascareñas
DOI:10.1021/ol007061m
日期:2001.2.1
[reaction: see text] Switching from a sulfinyl to a sulfonimidoyl group allows the reversal of the sense of asymmetricinduction in thermal [5C + 2C] intramolecular pyrone-alkene cycloadditions. Removal of the sulfoximine unit from the resulting cycloadducts yields optically active oxabicyclic systems that are enantiomeric to those obtained using the sulfinyl chiral auxiliary.