Dephosphonylation of α-fully substituted β-keto phosphonates with LiAlH4; regioselective alkylation of ketones employing phosphonate as a temporary activating group
作者:Shi Yong Lee、Jong Eoun Hong、Won Bum Jang、Dong Young Oh
DOI:10.1016/s0040-4039(97)00975-1
日期:1997.6
Alkylation of β-keto phosphonates is performed by teatment of β-keto phosphonates with n-BuLi, followed by addition of alkyl halides. The acquired α-fully substituted β-keto phosphonates are dephosphonylated by treatment of the lithium enolates with LiAlH4, followed by quenching with aqueous H2SO4 solution. This whole procedure represents a new route to regioselective alkylation of ketones.
β-酮膦酸酯的烷基化是通过用n -BuLi乳化β-酮膦酸酯,然后添加烷基卤来进行的。通过用LiAlH 4处理烯醇锂,然后用H 2 SO 4水溶液淬灭,将获得的α-完全取代的β-酮膦酸酯脱膦酰化。整个过程代表了酮区域选择性烷基化的新途径。
Phase Transfer Catalyzed Alkylation of 2-(Diethoxyphosphinyl)cyclohexane
作者:Suzanne M. Ruder、Vithalanand R. Kulkarni
DOI:10.1055/s-1993-25972
日期:——
Alkylation of cyclic ß-oxophosphonates using the ion pair extractive-phase transfer catalysis method was studied using 2-(diethoxyphosphinyl) cyclohexanone as the model compound. Unlike related phosphonic acid derivatives, the cyclic ß-oxophosphonates exhibited ambident character under phase transfer conditions when dichloromethane was used as the solvent. Carbon alkylation was most effective when activated and sterically less demanding alkyl halides were utilized.
A new methodology has been developed for the P-C bond cleavage of beta-carbonyl phosphonates. The alpha,alpha-disubstituted beta-keto phosphonates and the alpha-carbamoyl phosphonates have been shown to undergo dephosphonylation by reaction of their lithium enolate with LiAlH4, followed by quenching with aqueous H2SO4, affording regioselectively alpha,alpha-disubstituted ketone and alpha-substituted and alpha,alpha-disubstituted secondary amides.