Synthesis of (伪,伪-Difluoropropargyl)phosphonates via Aldehyde-to-Alkyne Homologation

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• 作者：Romana Pajkert ; Gerd-Volker R枚schenthaler
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：April 19, 2013
• 年：2013
• 卷：78
• 期：8
• 页码：3697-3708
• 全文大小：483K
• 年卷期：v.78,no.8(April 19, 2013)
• ISSN：1520-6904

文摘

An efficient synthetic methodology to a series of novel alkynes bearing a difluoromethylenephosphonate function via a Corey鈥揊uchs-type sequence starting from (diethoxyphosphoryl)difluoroacetic aldehyde is described. Dehydrobromination of the intermediate (3,3-dibromodifluoroallyl)phosphonate with potassium tert-butoxide gave rise to the corresponding bromoalkyne, whereas upon treatment with lithium base, the generation of ((diethoxyphosphoryl)difluoropropynyl)lithium has been achieved for the first time. The synthetic potential of this lithium reagent was further demonstrated by its reactions with selected electrophiles such as aldehydes, ketones, triflates, chlorophosphines, and chlorosilanes, leading to the corresponding propargyl phosphonates in good to excellent yields. However, in the case, of sterically hindered aldehydes, (伪-fluoroallenyl)phosphonates were the solely isolated products.