Template effect of Pd(II) in the synthesis of differently substituted enantiopure γ-butyrolactones and its synthetic applications
作者:Guoxin Zhu、Xiyan Lu
DOI:10.1016/0957-4166(95)00210-g
日期:1995.7
Under the catalysis of Pd(II) in the presence of CuX(2) and LiX, 1'-substituted allylic 2-alkynoates undergo stereoselective cyclization affording beta, gamma-disubstituted alpha-alkylidene-gamma-butyrolactones with cis or trans relative configurations. A highly efficient hydrogenation reaction of the cyclization product afforded a trans-alpha, beta-disubstituted-gamma-butyrolactone in quantitative yield with high stereoselectivity. Isohomopilopic acid which can be converted into isopilocarpine was synthesized using this methodology by further transformation.