Fig. 2: Optimization of reaction conditions.
From: Copper(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of 1,3-enynes and azomethine ylides
Reaction conditions: 1a–1a” (0.13 mmol), 2a (0.10 mmol). Yields were determined by 1H NMR analysis of the reaction crude mixture using CH2Br2 as an internal standard. Ee and dr were determined by chiral-stationary-phase HPLC analysis. THF = tetrahydrofuran, DCM = dichloromethane, DCE = ClCH2CH2Cl. Barton’s base = 2-tbutyl-1,1,3,3-tetramethylguanidine. a0.4 M. bIsolated yield.
