An efficient alternative to DBU in the oxathiaphospholane (OTP) method for the solid phase synthesis of P-stereodefined phosphorothioate analogs

Abstract

This study presents a modified (extended) 1,3,2-oxathiaphospholane (OTP) method for the synthesis of P-stereodefined phosphorothioate analogs in the presence of previously unused organic bases. TBD (5,7-triazabicyclo[4.4.0]dec-5-ene) and Verkade's proazaphosphatrane (2,8,9-trimethyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane) are herein used for the first time as efficient organic bases compared to DBU, which is commonly used in the OTP approach.