First Stereoselective Synthesis of Diethyl cis- and trans-(4-Hydroxy-1,2,3,4-tetrahydroquinolin-2-yl)phosphonates and Ethyl Phenylphosphinates from Quinolin-4(1H)-one

Abstract

AbstractWe report a practical method for the first stereoselective synthesis of diethyl cis- and trans-(4-hydroxy-1,2,3,4-tetrahydroquinolin-2-yl)phosphonates, as well as ethyl cis- and trans-(4-hydroxy-1,2,3,4-tetrahydroquinolin-2-yl)phenylphosphinates. The main feature of this method is the regioselective 1,4-phosponylation to N-Cbz quinolin-4(1H)-one using diethyl phosphite or ethyl phenylphosphinate followed by a highly diastereoselective reduction to give the cis stereoisomers as favored products, which were converted into trans stereoisomers through the Mitsunobu reaction. Cleavage of the N-Cbz bond under hydrogenolysis gave the target heterocyclic α-aminophosphonates and α-aminophosphinates.