One-carbon homologation of unsymmetrical ketones through magnesium β-oxido carbenoid rearrangement and trapping the enolate intermediates with electrophiles
作者:Shu Tanaka、Takehiro Anai、Makoto Tadokoro、Tsuyoshi Satoh
DOI:10.1016/j.tet.2008.05.079
日期:2008.7
A procedure for one-carbon homologation of unsymmetrical ketones, including one-carbon ring-expansion of 2-substituted cyclohexanones, through magnesium β-oxido carbenoid rearrangement as the key reaction is described. Addition of the α-sulfinyl carbanion of 1-chloroethyl p-tolyl sulfoxide to an unsymmetrical ketone gave two diastereomers as adducts in good yields. The adducts were treated with a base
描述了一种通过不对称酮的一碳同系化(包括2-取代的环己酮的一碳环扩展)通过镁β-氧化类胡萝卜素重排作为关键反应的方法。1-氯乙基p的α-亚磺酰基碳负离子的加成甲苯磺酸亚砜制得不对称酮后,以高收率得到了两种非对映异构体作为加合物。将加合物用碱处理以得到醇盐,将其用格氏试剂处理以得到β-氧化类胡萝卜素镁。然后进行β-氧化类胡萝卜素重排,以提供在α-位具有甲基的一碳同系酮。在重排中观察到显着的特异性或选择性。发现该反应的烯醇镁中间体能够被数种亲电试剂捕获,从而得到一碳同系的α,α-二取代的酮。还讨论了特异性和选择性的起源。