Treatment of ether-bridged cyclooctatrienes (formed via intramolecular [4 + 4]-photocycloaddition of pyran-2-ones bearing pendent furans, followed by thermal decarboxylation) with excess MeLi furnishes triquinane ring systems via an apparent sequence of beta-elimination, 1,5-hydrogen shift, and transannular aldolization.
Diastereocontrol in [4+4]-photocycloadditions of pyran-2-ones: effect of ring substituents and chiral ketal
作者:Lei Li、John A. Bender、F.G. West
DOI:10.1016/j.tetlet.2008.12.117
日期:2009.3
4-Mesyloxypyran-2-ones joined to furan by a three-carbon linker undergo intramolecular-crossed [4+4]-photocycloaddition with high or complete selectivity for the exo cycloadcluct. When a C-2-symmetric ketal was present on the tether adjacent to the pyranone ring, moderate levels of asymmetric induction were obtained. (C) 2009 Elsevier Ltd. All rights reserved.
Cyclooctatrienes from pyran-2-ones via a tandem [4 + 4]-photocycloaddition/decarboxylation process
作者:Lei Li、Charles E. Chase、F. G. West
DOI:10.1039/b806871b
日期:——
Irradiation of pyran-2-ones bearing pendent furans in aqueous MeOH followed by heating furnished fused bicyclic products containing a cyclooctatriene ring.
Treatment of ether-bridged cyclooctatrienes (formed via intramolecular [4 + 4]-photocycloaddition of pyran-2-ones bearing pendent furans, followed by thermal decarboxylation) with excess MeLi furnishes triquinane ring systems via an apparent sequence of beta-elimination, 1,5-hydrogen shift, and transannular aldolization.