Synthesis of α-fluoro-β, γ-alkenylphosphonates and conjugated fluoroenynes from a common intermediate (α-fluoropropargyl) phosphonate
摘要:
The efficient preparation of alpha-fluoro-beta,gamma-alkenylphosphonate 3, via catalytic hydrogenation of (alpha-fluoropropargyl)phosphonate ester 1, is described. Conjugated fluoroenynes 4 have been synthesized using a modified Horner Wadsworth Emmons (HWE) olefination of aldehydes or ketones and 1 in relatively good yields. Yields were lowered because of the formation of alpha-fluoro-gamma-hydroxyallenylphosphonate 5 during the reaction. The nature of the counterion was very important in the outcome of the HWE reaction; better yields of fluoroenynes were obtained when a potassium base was used instead of a lithium base. (C) 1998 Elsevier Science Ltd. All rights reserved.
The preparation of (EtO)2P(O)CFHZnBr and (EtO)2P(O)CFHCu and their utility in the preparation of functionalized α-fluorophosphonates
作者:Xin Zhang、Weiming Qiu、Donald J. Burton
DOI:10.1016/s0040-4039(99)00305-6
日期:1999.4
The organometallic reagent, (EtO)2P(O)CFHZnBr, was generated in situ in excellent yields via the reaction of (EtO)2P(O)CFHBr with zinc metal. Metathesis with Cu(I)Br gave (EtO)2P(O)CFHCu. The reagents exhibit excellent reactivity with substrates, such as allyl halides, alkynyl halides, vinyl halides, aryl halides and acyl or phosphoryl halides, and provide a useful one flask route to functionalized