Cationic-Oxazaborolidine-Catalyzed Enantioselective Diels-Alder Reaction of α,β-Unsaturated Acetylenic Ketones
作者:Joshua N. Payette、Hisashi Yamamoto
DOI:10.1002/anie.200904339
日期:2009.10.12
Yne also a good dienophile: The cationic oxazaborolidine 1 promoted the formation of Diels–Alder adducts between acetylenic ketones and both cyclic and acyclic dienes in excellent yield with 99 % ee (see scheme; Tf=trifluoromethanesulfonyl, TMS=trimethylsilyl). Importantly, high levels of asymmetric induction were also observed with dienophiles that lacked the typical hydrogen‐bonding motif required
炔也是很好的亲双烯体:阳离子恶唑硼烷1推动的炔酮和环状和无环二烯烃之间狄尔斯-阿德耳加合物的形成的优良率以99%的 ee值(参见方案; TF =三氟甲磺酰基,TMS =三甲基甲硅烷)。重要的是,在缺乏其他 oxazaborolidinium 介导的反应所需的典型氢键基序的亲二烯体中也观察到了高水平的不对称诱导。