Cyclisation of acetylenecarboxylic acid. Synthesis of γ-methylenebutyrolactones
作者:Makoto Yamamoto
DOI:10.1039/p19810000582
日期:——
Various γ-exo-methylenebutyrolactones have been synthesized in excellent yield by the cyclisation of acetylenecarboxylic acids in the presence of a catalytic amount of mercury(II) oxide. Cyclisation of terminal acetylene compounds[e.g.(1a)–(1e)]proceeded regioselectively to give γ-exo-methylenebutyrolactones as the sole product. Disubstituted acetylenes [(1f)–(1i)] also gave the (Z)-configurational
各种γ -外型-methylenebutyrolactones已经在良好产率的乙炔基酸中的汞(催化量存在环化合成了II)氧化物。末端乙炔化合物环化[例如(1A) - (1E)]区域选择性地得到进行γ -外型-methylenebutyrolactones作为唯一的产物。二取代的乙炔[(1F) - (1i)中]也给出了(Ž)-configurational烯醇内酯,但少量的(的Ë)一-异构体γ -外烯醇内酯和δ内酯(α吡喃酮)也成立了。exo的光谱性质和立体化学还讨论了-烯醇内酯。