Palladium-catalyzed cyclization of .omega.-olefinic tosamides. Synthesis of nonaromatic nitrogen heterocycles
作者:Louis S. Hegedus、James M. McKearin
DOI:10.1021/ja00373a019
日期:1982.5
Conformationally Constrained β-Amino Acid Derivatives by Intramolecular [2 + 2]-Photocycloaddition of a Tetronic Acid Amide and Subsequent Lactone Ring Opening
作者:Birte Basler、Oliver Schuster、Thorsten Bach
DOI:10.1021/jo0515226
日期:2005.11.1
N-3-alkenyltetronic acid amides 9 and 12 were prepared from tetronic acid bromide (7) and the corresponding amines 6 and 10 by nucleophilic substitution and subsequent acylation in 71% and 39% overall yield. They underwent an intramolecular [2 + 2]-photocycloaddition upon direct irradiation (λ = 254 nm) to yield diastereoselectively the strained lactones 15 (76%) and 16 (91%) with a 2-azabicyclo[3.2.0]heptane core