Chroman-4-ones via Microwave-Promoted Domino Claisen Rearrangement–Oxa-Michael Addition: Synthesis of Tabchromones A and B
作者:Bernd Schmidt、Martin Riemer、Uwe Schilde
DOI:10.1055/s-0034-1379364
日期:——
Allylphenyl ethers with a pendant enone substituent undergo, upon microwave irradiation, a domino sequence of Claisenrearrangement and 6-endo-trig-cyclization to furnish functionalized chroman-4-ones. The natural products tabchromones A and B were synthesized via this method.
The preparation of three types of cyclic alkenols, (S)-2-cyclohexenol, (R)-2,5-dihydrobenzo[b]oxepin-5-ol, and (R)-5,6-dihydro-2H- benzo[b]oxocin-6-ol, has been accomplished in enantiomerically pure forms as model compounds using a combination of a lipase-catalyzed reaction and a ring closing olefin metathesis (RCM) reaction. (c) 2007 Elsevier Ltd. All rights reserved.