Vanessa F. Hawkins, M. Wilkinson, M. Whiting
Sep 19, 2008
Citations
0
Influential Citations
15
Citations
Journal
Organic Process Research & Development
Abstract
Quenching of aryl Grignard reagents with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (isopropyl pinacol borate) under noncryogenic conditions can lead to mixtures of the corresponding boronic ester along with, generally undesired, borinic acid derivatives. We have found that in certain cases gentle heating of the crude reaction mixtures leads to complete equilibration to give the borinic esters as the sole product which can then be isolated in high yield. This novel equilibration can reduce the need for use of cryogenic conditions or large excesses of reagents to obtain selectivity during boronic ester syntheses.