作者:Francisco Camps、Josep Coll、Amadeu Llebaria、Josep M. Moretó、Susagna Ricart
DOI:10.1055/s-1989-27168
日期:——
The title compounds 3a-d can be satisfactorily prepared by the reaction of lithium alkoxyacetylides with methyl chloroformate in tetrahydrofuran at - 78°C, in the presence of a 3.5 molar excess of lithium bromide (based on chloroformate). Moderate to good yields of 3a-d were obtained according to the product stabilities. However, methyl tert-butoxyacetylenecarboxylate (3e) was too unstable to be isolated. The putative dual role of the lithium salt and the formation of substantial amounts of carbonates, observed in its absence, are discussed.
标题化合物3a-d可以通过在-78°C下,在四氢呋喃中,锂醇基乙炔与甲基氯甲酸酯反应,并在氯甲酸酯基础上加入3.5倍摩尔过量的锂溴化物来令人满意地制备。根据产物的稳定性,3a-d的产率从中等到良好不等。然而,甲基叔丁氧基乙炔羧酸酯(3e)过于不稳定,无法被分离出来。锂盐的假设双重作用以及在没有它的情况下观察到的大量碳酸盐的形成,都在讨论之列。