Domino conversions of allyl tetronates and 4-allyloxycoumarins to all-trans 1,3,4,5-tetrasubstituted γ-butyrolactams
作者:Rainer Schobert、Arno Bieser、Gillian Mullen、Gary Gordon
DOI:10.1016/j.tetlet.2005.06.055
日期:2005.8
All-trans 1,3,4,5-tetrasubstituted γ-butyrolactams 3 and 7 are readily available in one-pot fromallyltetronates or 4-allyloxycoumarins and amines via a four-step domino Claisen–Conia ring-opening transamidation reaction.
Microwave-accelerated Claisen rearrangements of allyl tetronates and tetramates
作者:Rainer Schobert、Gary J. Gordon、Gillian Mullen、Ralf Stehle
DOI:10.1016/j.tetlet.2003.12.024
日期:2004.2
[3,3]-Sigmatropic rearrangements of allyltetronates and allyl tetramates to give 3-allyltetronic or -tetramic acids, respectively, proceed within 20–60 min under microwave irradiation (300 W, 130–190 °C). Consecutive (homo)sigmatropic [1,5] H-shifts such as oxa-ene reactions are promoted less effectively, which allows the isolation of Claisen intermediates of sigmatropic domino sequences, in contrast