The reaction of benzofuranyldiazoacetates with 1,3-dienes catalyzed by the dirhodium tetracarboxylate Rh2(R-DOSP)4, generates formal [4+3] cycloadducts with >94% de and 91-98% ee. The reaction proceeds by a tandem cyclopropanation/Cope rearrangement followed by a stereoselective tautomerization. This methodology was extended to a formal synthesis of (+)-frondosin B.
苯并呋喃基
重氮乙酸酯与四
羧酸二
铑Rh2(R-
DOSP)4催化的1,3-二烯发生反应,生成正式的[4 + 3]环加合物,其de> 94%,ee为91-98%。该反应通过串联
环丙烷化/ Cope重排,随后进行立体选择性互变异构而进行。此方法扩展到(+)-fron
DOSin B的形式合成。