Rapid Entry into Biologically Relevant α,α-Difluoroalkylphosphonates Bearing Allyl Protection–Deblocking under Ru(II)/(IV)-Catalysis
摘要:
A convenient synthetic route to a,a-difluoroalkylphosphonates is described. Structurally diverse aldehydes are condensed with LiF2CP(O)-(OCH2CH=CH2)(2). The resultant alcohols are captured as the pentafluorophenyl thionocarbonates and efficiently deoxygenated with HSnBu3, BEt3, and O-2, and then smoothly deblocked with CpRu(IV)(pi-allyl)quinoline-2-carboxylate (1-2 mol %) in methanol as an ally! cation scavenger. These mild deprotection conditions provide access to free alpha,beta-difluoroalkylphosphonates in nearly quantitative yield. This methodology is used to rapidly construct new bis-alpha,alpha-difluoroalkyl phosphonate inhibitors of PTPIB (protein phosphotyrosine phosphatase-1B).