Single-electrontransferreactions between tritylanion and 1-acyl-2,2-dimethylaziridines provide, among other products, the methallyl amides 7 and the triphenylmethanes 8 carrying an amidoethyl chain attached with the tertiary carbon ortho to the triphenylmethane.
A two-step reaction sequence for the highly stereodivergent construction of 1,3-diamines with three continuous stereocenters is reported. This novel method enables the controlled synthesis of any given diastereomer of the 1,3-diamine scaffold from a simple set of starting materials in a highly modular manner. The disclosed approach is based on the reaction of an enamide with an in situ generated N-acylimine
the oxysulfonylated products in moderate to excellent yields. Moreover, the direct incorporation of sulfurdioxide into the sulfonylated products via organolithium chemistry has been achieved. The formed N-O-acetals are competent acylimine precursors. Their utilization as building blocks for the synthesis of biologically relevant β-amidosulfones is described as well.
Nucleophilic cleavage of 2,2-dimethylaziridines: competition between SN2 and postulated “SET” mechanism.
作者:H. Stamm、P. Assithianakis、B. Buchholz、R. Weiβ
DOI:10.1016/s0040-4039(00)85562-8
日期:1982.1
Regioselectivity of nucleophilic attack on 2,2-dimethylaziridines depends on the degree of leaving group activation: in highly activated aziridines it occurs at the methylene carbon and in less activated at the tertiary carbon. This latter abnormalringopening is explained by an SET mechanism.
A bismuth(III) triflate catalyzed three-component synthesis of α-substituted amides starting from amides, aldehydes, and (hetero)arenes is reported. The reaction has a broad substrate scope, encompassing formaldehyde as well as aryl and alkyl aldehydes. Low catalyst loadings are required, and water is formed as the only side product. The scope and limitation of this method will be discussed.