The first synthesis of enantiomerically pure cyclopropylphosphonate analogues of nucleotides via asymmetric cyclopropanation of chiral (1-diethoxyphosphoryl)vinyl p-tolyl sulfoxide
(S)-(+)-(1-Diethoxyphosphoryl)vinyl p-tolyl sulfoxide undergoes cyclopropanation with ethyl (dimethylsulfuranylidene)acetate (EDSA) in a highly diastereoselective manner (facial stereoselectivity up to 12:1). The major diastereomer obtained in this reaction, (1S,2S)-(1-diethoxyphosphoryl-2-ethoxycarbonyl)cyclopropyl p-tolyl sulfoxide, was converted in three steps into enantiopure cyclopropylphosphonate analogues of purine nucleotides as the constrained forms of antiviral 1-alkenylphosphonic acid derivatives of purines. (C) 2003 Elsevier Science Ltd. All rights reserved.