An alkynylboronate cycloaddition strategy to functionalised benzyne derivatives
作者:James D. Kirkham、Patrick M. Delaney、George J. Ellames、Eleanor C. Row、Joseph P. A. Harrity
DOI:10.1039/c0cc01345e
日期:——
A new approach to benzyne precursors has been developed that involves the [4+2] cycloaddition of trimethylsilyl alkynylboronates with 2-pyrones, followed by oxidation and trifluoromethylsulfonylation of the boronate moiety.
remarkable feature of new precursors is the selective generation of 3-haloarynes by suppressing the competitive thia-Fries rearrangement, which is the problem in the reaction using the well-known 3-haloaryne precursors. The advantage of new precursor 2a over a typical precursor 1 was confirmed by the direct comparisons in several reactions. The application of precursors 2a–2h to the syntheses of heterocycles