Synthesis of Furan-Bridged 10-Membered Rings through [8 + 2]-Cycloaddition of Dienylfurans and Acetylenic Esters
作者:Lei Zhang、Yu Wang、Clare Buckingham、James W. Herndon
DOI:10.1021/ol050416n
日期:2005.4.14
The coupling of various dienylfurans with dimethyl acetylenedicarboxylate (DMAD) has been examined. In most cases this reaction proceeds via [8 + 2]-cycloaddition to afford furan-bridged 10-membered ring systems as a single diastereomer. Dienylfuran intermediates were generated using either a chromium carbene-based method or aldol-based methods. Reaction of [8 + 2]-cycloadducts with electrophilic reagents occurred selectively at the enol ether alkene.
Coupling of Fischer Carbene Complexes with Conjugated Enyne−Aldehydes and Ketones: A Novel Synthesis of Furan Derivatives