The Participation of Alkynylboronates in Inverse Electron Demand [4 + 2] Cycloadditions: A Mechanistic Study
作者:Enrique Gomez-Bengoa、Matthew D. Helm、Andrew Plant、Joseph P. A. Harrity
DOI:10.1021/ja068527k
日期:2007.3.1
The participation of alkynylboronates in [4 + 2] cycloadditions has been investigated using both kinetic and DFT studies. Kinetic studies of the cycloaddition of tetrazine 1 with alkynylboronate 2 strongly suggest that a concerted cycloaddition mechanism is in operation. This mechanism has been confirmed by DFT calculations; moreover, a highly synchronous transition state appears to operate in this
Ambient Temperature Nitrogen-Directed Difluoroalkynylborane Carboni−Lindsey Cycloaddition Reactions
作者:Jérôme F. Vivat、Harry Adams、Joseph P. A. Harrity
DOI:10.1021/ol902573x
日期:2010.1.1
The in situ generation of alkynyldifluoroboranes in the presence of N-heterocycle substituted tetrazines provides a convenient and direct method for the synthesis of pyridazine difluoroboranes. The reactions proceed In 10 min under ambient conditions and provide the opportunity to assemble unsymmetrical products with complete regiocontrol.