Regioselective Synthesis of 3-Carbo-5-phosphonylpyrazoles through a One-Pot Claisen-Schmidt/1,3-Dipolar Cycloaddition/Oxidation Sequence
作者:Anthony R. Martin、Kishor Mohanan、Loic Toupet、Jean-Jacques Vasseur、Michael Smietana
DOI:10.1002/ejoc.201100167
日期:2011.6
A one-pot reaction involving an aldehyde, a methyl ketone, and the Bestmann-Ohira reagent has been developed for the synthesis of variously substituted 3-carbo-5-phosphonylpyrazoles. Our synthetic methodology features a domino Claisen- Schmidt/1,3-dipolar cycloaddition/oxidationsequence,which leads to the target compounds in excellent yields. We further demonstrated that this unprecedented sequence
A novel and efficient reaction of vinyl azides with Bestmann-Ohira reagent for the regioselectivesynthesis of phosphonylpyrazoles is presented. Reaction proceeds through 1, 3 dipolar cycloaddition with an excellent yield in short period of time under mild reaction conditions. Moreover, no column purification is involved for the isolation of products.