A new method for synthesis of α,α-disubstituted carbonyl compounds from carbonyl compounds with one-carbon homologation through β-oxido carbenoid rearrangement as the key reaction
作者:Kohsuke Miyashita、Tsuyoshi Satoh
DOI:10.1016/j.tet.2005.03.054
日期:2005.5
with electrophiles such as aldehydes, ethyl chloroformate, benzoyl chloride, haloalkanes to give α,α-disubstituted carbonyl compounds in moderate to good yields. This method provides a new and efficient way for synthesis of α,α-disubstituted carbonyl compounds from carbonyl compounds with one-carbon homologation in only two synthetic operations.
羰基化合物与1-氯烷基对甲苯基亚砜的α-亚磺酰基锂的加成反应以高到定量的产率得到加合物α-氯β-羟基亚砜。首先用碱处理加合物,得到醇盐,然后用i -PrMgCl或t处理。-BuLi通过亚砜-金属交换反应生成β-氧化类胡萝卜素。然后进行β-氧化类胡萝卜素重排以提供具有一碳延伸的烯醇化物。发现烯醇酸酯中间体能够被亲电子试剂例如醛,氯甲酸乙酯,苯甲酰氯,卤代烷烃捕获,以中等至良好的产率得到α,α-二取代的羰基化合物。该方法提供了一种新颖有效的方法,仅需两次合成操作,即可从羰基化合物中合成具有碳原子同构关系的α,α-二取代羰基化合物。