Enantioselective ring construction: synthesis of halogenated marine natural spiro[5.5]undecane sesquiterpenes
作者:Julio D. Martin、Cirilo. Perez、Jose L. Ravelo
DOI:10.1021/ja00284a052
日期:1986.11
(-)-33, and (8R,9R)-8-bromo-9-hydroxy-(E)-y-bisabolene, (+)-33, as the basic building blocks. This asymmetric methodology represents a general strategy for the enantioselective construction of spiro[5S]undecane systems containing a chiral quaternary center. This approach should be generally useful for the preparation of a wide variety of six-membered spirocycle-containing natural compounds. The compounds
本研究的主要目标是开发一种通用方法,以在溴鎓引发的分子内碳环化反应中实现大量的不对称诱导。该目标已通过生成包含位于环己烯环上的两个立体原原子的环外亚烷基来实现。该过程的立体化学已经进行了一些详细的研究,并且全合成 (-)-(2R,6S,8S,9S)-2,8-dibromo-9-hydroxy-cr-chamigrene (9) , (- )-(2R,6S,8S,9S)-2,8-dibromo-9-hydroxy-fl-chamigrene (lo), (-)-(2R,6S)-2-bromo-fl-chamigrene (5), (-)-P-chamigrene (6) 及其相应的 (+)-11、-12、-7 和 -8 对映异构体首次被描述。这些化合物由 (8S,9S)-8-bromo-9-hydroxy-(E)-y-bisabolene、(-)-33 和 (8R,9R)-8-bromo-9