Untersuchungen in der Bicyclo-[2,2,2]-octan Reihe. 1. Mitteilung. Synthese von Bicyclo-[2-2-2]-octadien-(2,5) durch cis-Eliminierung
作者:C. A. Grob、H. Kny、A. Gagneux
DOI:10.1002/hlca.19570400116
日期:——
Pure bicyclo-[2,2,2]-2,5-octadiene (I), m. p. 57°, has been prepared (a) by treatment of trimethyl-bicyclo-5-octenyl-2-ammonium chloride (IIIa) with phenyllithium, (b) by Hofmann degradation of the corresponding quaternary base IIIc and (c) by thermal decomposition of the N-oxide of 2-dimethylamino-bicyclo-5-octene (V).
Oxathiaborolium-Catalyzed Enantioselective [4 + 2] Cycloaddition and Its Application in Lewis Acid Coordinated and Chiral Lewis Acid Catalyzed [4 + 2] Cycloaddition
作者:Ramalingam Boobalan、Rong-Jie Chein
DOI:10.1021/acs.orglett.1c02345
日期:2021.9.3
catalysts for [4 + 2] cycloaddition. Oxathiaborolium pentachlorostannate (5–10 mol %) successfully catalyzed cycloaddition of various dienes and dienophiles to afford cycloadducts with excellent enantioselectivity (20 examples, up to 99% ee). This super Lewis acid also exhibited good enantioselectivity for the first Lewis acid coordinated and chiral Lewis acid catalyzed [4 + 2] cycloaddition to α,β-unsaturated