Lewis Base Catalyzed Aerobic Oxidative Intermolecular Azide-Zwitterion Cycloaddition
作者:Wenjun Li、Jian Wang
DOI:10.1002/anie.201408265
日期:2014.12.15
discovery of a novel aerobic oxidative intermolecular azide–zwitterion reaction catalyzed by an organocatalyst is presented. It is demonstrated that the merger of the Lewis base 1,8‐diazabicyclo[5.4.0]undec‐7‐ene and electron‐deficient olefins generates reactive zwitterion intermediates, which readily participate in cycloaddition reactions with an array of azides, thus providing facile entry to fully or
Strain-Activated Diels–Alder Trapping of 1,2-Cyclohexadienes: Intramolecular Capture by Pendent Furans
作者:Verner A. Lofstrand、Kyle C. McIntosh、Yaseen A. Almehmadi、F. G. West
DOI:10.1021/acs.orglett.9b02085
日期:2019.8.16
Intramolecular [4 + 2] cycloaddition reactions of substituted 1,2-cyclohexadienes with pendent furans enables the synthesis of complex tetracyclic scaffolds in a single step under mild conditions. All Diels–Alder cycloadducts were obtained as single diastereomers, assigned as the endo isomer. Substrates were easily assembled via Stork–Danheiser alkylation of 3-ethoxy-2-bromocyclohex-2-enone to accommodate