A Mild and Regiospecific Synthesis of Pyrazoleboranes.
Andrew W BrownJúlia Comas-BarcelóJoseph P A HarrityPublished in: Chemistry (Weinheim an der Bergstrasse, Germany) (2017)
Alkynylboranes show unprecedented reactivity in their [4+2] cycloaddition of sydnones offering access to fully substituted pyrazoles within a few hours at room temperature. This method delivers synthetically valuable pyrazoleboranes with complete control of regioselectivity, and these intermediates can be further elaborated through functionalization of the C-B bond.