Biocatalytic syntheses of chiral non-racemic 2-hydroxyalkanephosphonates
摘要:
A series of 2-oxoalkanephosphonates 2 were screened for reduction with Geotrichum candidum. Only diethyl 2-oxopropanephosphonate 2a underwent asymmetric reduction to give (+)-(R)-diethyl 2-hydroxypropanephosphonate 3a with 98% e.e. In turn, a series of racemic 2-hydroxyalkanephosphonates 3 were acetylated under kinetic resolution conditions in the presence of various lipases to give the corresponding 2-acetoxyalkanephosphonates 4 and recovered alcohols 3 in good yields and with e.e. up to 93%. (C) 2002 Elsevier Science Ltd. All rights reserved.
β-Ketophosphonate Formation via Aerobic Oxyphosphorylation of Alkynes or Alkynyl Carboxylic Acids with H-Phosphonates
摘要:
A synergistic Cu/Fe-catalyzed aerobic oxyphosphorylation of alkynes or alkynyl carboxylic acids with H-phosphonate is disclosed. The useful beta-ketophosphonate products were obtained in good yields under oxygen atmosphere in a novel way. This reaction exhibits a wide substrate scope, and the mechanistic experiments indicate that a radical mechanism forms both C-P and C=O bonds simultaneously. This mechanism contrasts existing aerobic difunctionalization of alkynes.
Aboujaoude, Elie Elia; Collignon, Noel; Teulade, Marie-Paule, Phosphorus and Sulfur and the Related Elements, 1985, vol. 25, p. 57 - 62
作者:Aboujaoude, Elie Elia、Collignon, Noel、Teulade, Marie-Paule、Savignac, Philippe
DOI:——
日期:——
SmI2-mediated reactions of diethyl iodomethylphosphonate with esters and lactones: a highly stereoselective synthesis of a precursor of the C-glycosyl analogue of thymidine 5′-(β-l-rhamnosyl)diphosphate
作者:Fulvia Orsini、Alessandro Caselli
DOI:10.1016/s0040-4039(02)01540-x
日期:2002.9
In the presence of samarium iodide diethyl iodomethylphosphonate reacts with esters to afford beta-ketophosphonates. The protocol has been applied to sugar lactones to afford in fairly good yields intermediates that are useful precursors for a variety of potentially bioactive compounds, such as the C-glycosyl analogue of thymidine 5'-(beta-L-rhamnosyl)diphosphate. (C) 2002 Elsevier Science Ltd. All rights reserved.