Highly enantioselective intermolecular Cu (I)-catalyzed cyclopropanation of cyclic enol ethers. Asymmetric total synthesis of (+)-Quebrachamine

O Temme, SA Taj, PG Andersson

文献索引：Temme, Oliver; Taj, Shabbir-Ali; Andersson, Pher G. Journal of Organic Chemistry, 1998 , vol. 63, # 17 p. 6007 - 6015

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被引用次数: 61

摘要

A set of cyclic enol ethers derived from 2, 3-dihydrofuran 35 and 3, 4-dihydropyran 8 with a varying substitution pattern at the olefinic system were synthesized. Evans's ligand 5 with Cu (I) OTf was found to be an effective catalyst in the cyclopropanation reaction between cyclic enol ethers 14, 19, 28-31, and 33 and ethyl diazoacetate 6 to give diastereoselectivities up to exo/endo= 95: 5 and enantioselectivities higher than 95% in nearly all cases. Because ...