A novel visible-light-induced aza-pinacol rearrangement was developed for the first time. In this approach, the addition of the N-centered radical to the C═C bond of alkylidenecyclopropanes delivers a variety of cyclobutanimines and γ-butyrolactones, with all-carbon quaternary centers via the ringexpansion of the cyclopropyl group, in moderate to good yields under mild reaction conditions.
Direct Synthesis of Methylene-1,2-dichalcogenolanes via Radical [3 + 2] Cycloaddition of Methylenecyclopropanes with Elemental Chalcogens
作者:Lei Yu、Yulan Wu、Tian Chen、Yi Pan、Qing Xu
DOI:10.1021/ol3031846
日期:2013.1.4
Direct [3 + 2] radical cycloaddition of methylenecyclopropanes and elemental chalcogens (S, Se, Te) can readily occur under simple thermal conditions, providing an efficient, practical method for preparation of useful but not easily accessed methylene-1,2-dichalcogenolanes.
Stereoselective Aminobromination of Alkylidenecyclopropanes with TsNH<sub>2</sub>and NBS as Nitrogen and Bromine Sources: A Simple Access to γ-Bromohomoallylic Sulfonamides
作者:Xian Huang、Wei-Jun Fu
DOI:10.1055/s-2006-926350
日期:——
A convenient and efficient method for aminobromination of alkylidenecyclopropanes is reported. This is exemplified in the stereoselective preparation of N-[(Z)-3-bromobut-3-en-1-yl]-p-toluenesulfonamides by using p-toluenesulfonamide (TsNH2) and N-bromosuccinimide (NBS) as nitrogen and bromine sources, respectively.
Iron salt, a cheap, highly efficient and environment-friendly metal catalyst for Se–Se bond cleavage and the further reaction with methylenecyclopropanes under mild conditions
FeCl3 was found to be a good catalyst in Se-Se bond cleavage. Further electrophilic additions to methylenecyclopropanes provide a convenient access to diphenylselenylcyclobutanes. Comparing with other Lewis acids, FeCl3 is much cheaper and the reaction conditions are milde and more tolerance to air and moisture. (C) 2010 Elsevier B.V. All rights reserved.