(5,6-Dihydro-1,4-dithiin-2-yl)methanol as a Versatile Allyl-Cation Equivalent in (3+2) Cycloaddition Reactions
作者:Jan Hullaert、Johan M. Winne
DOI:10.1002/anie.201606411
日期:2016.10.10
instrumental for efficient cycloaddition reactions to take place, thus indicating an attractive strategy for controlling the reactivity of heteroatom‐substituted allyl cations. The formal cycloaddition reaction is highly regio‐ and stereoselective and was also used for a short totalsynthesis of the natural product cuparene in racemic form through a cycloaddition–hydrodesulfurization sequence.
Stereoselective Rhodium-Catalyzed Isomerization of Stereoisomeric Mixtures of Arylalkenes
作者:Tao Li、Wanxiang Zhao、Hongxuan Yang、Wenke Dong、Wencan Wang
DOI:10.1055/s-0040-1707166
日期:2020.10
Abstract A new efficient method for the synthesis of a high ratio of E-alkenes from E/Z mixtures of alkenes with B2pin2 in the presence of a rhodium catalyst is described. This reaction features mild reaction conditions, broad functional group tolerance, and highly great application potential.
Direct Organocatalytic Oxo-Metathesis, a<i>trans-</i>Selective Carbocation-Catalyzed Olefination of Aldehydes
作者:Veluru Ramesh Naidu、Juho Bah、Johan Franzén
DOI:10.1002/ejoc.201403651
日期:2015.3
been developed. The reaction is catalyzed by trityl tetrafluoroborate (TrBF4) and utilizes unactivatedalkenes for the olefination of aromatic aldehydes to give trans -alkylstyrenes in yields of 44-85% with only acetone as the byproduct. The pronounced Lewis acidity of the carbocation results in unusual reactivity that is proposed to catalyze a stepwise [2+2] cycloaddition to give an oxetane intermediate