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.
炔炔酮在其[4 + 2]
环戊烯酮的环加成反应中显示出前所未有的反应活性,可在室温下数小时内获得完全取代的
吡唑。该方法提供了对合成具有有价值的
吡唑硼烷,可以完全控制区域选择性,并且这些中间体可以通过C-B键的官能化进一步加工。