Stereospecific syntheses of (Z)- and (E)-4-bromomethylene-5,5-dimethyl-3-phenyloxazolidin-2-one
作者:Christopher C. Browne、Nazim Punja
DOI:10.1039/p19750001525
日期:——
1-dimethylprop-2-ynyl carbanilate undergoes base-catalysed cyclisation to give (Z)-4-bromomethylene-5,5-dimethyl-3-phenyloxazolidin-2-one. Bromination of 5,5-dimethyl-4-methylene-3-phenyloxazolidin-2-one, followed by dehydrobromination, gives the E-isomer. The stereoisomers have been characterised by n.m.r. spectroscopy. The stereospecificity of each reaction is rationalised in mechanistic terms.
3-溴-1,1-二甲基丙-2-炔基氨基甲酸酯经碱催化的环化反应生成(Z)-4-溴亚甲基-5,5-二甲基-3-苯基恶唑烷-2-酮。溴化5,5-二甲基-4-亚甲基-3-苯基恶唑烷基-2-酮,然后脱氢溴化,得到E-异构体。立体异构体已经通过核磁共振光谱法表征。每个反应的立体特异性从机理上讲是合理的。