An Efficient Synthesis of 2- and 2,6-Substituted Piperidines Using Pd<sup>II</sup>-Catalyzed 1,3-Chirality Transfer Reaction
作者:Sudhir M. Hande、Nobuyuki Kawai、Jun’ichi Uenishi
DOI:10.1021/jo801926g
日期:2009.1.2
An efficient and general method for 2- and 2,6-substituted piperidine syntheses using PdII-catalyzed 1,3-chirality transfer reaction has been developed. The various N-protected ζ-amino allylic alcohols cyclize in the presence of PdCl2(CH3CN)2 to give substituted piperidines with high stereoselectivities. The syntheses of (S)-(+)- and (R)-(−)-coniine were achieved in 3 steps from the optically pure
For the first time, intramolecular allylic amination was conducted using rhodium(III) according to an "inner-sphere" type mechanism with amines activated by only one electron-withdrawing group. The activation of C(sp(3))-H bonds was chemoselective and allows the access to a variety of substituted cyclic amines such as pyrrolidines and piperidines.
Mg(ClO4)2-catalyzed intramolecular allylic amination: application to the total synthesis of demethoxyfumitremorgin C
作者:Danfeng Jiang、Zhengren Xu、Yanxing Jia
DOI:10.1016/j.tet.2012.03.097
日期:2012.6
A Mg(ClO4)2-catalyzed intramolecularamination of allylic alcohols with carbamate or sulfonamide nucleophiles to form substituted piperidine and pyrrolidine derivatives has been developed. This method has been successfully applied to the total synthesis of demethoxyfumitremorgin C.
The eco-friendly and highly diastereoselective synthesis of substituted cis-2,6-piperidines and cis-2,6-tetrahydropyrans is described. The key step of this method is the iron-catalyzed thermodynamic equilibration of 2-alkenyl 6-substituted piperidines and 2-alkenyl 6-substituted tetrahydropyrans allowing the isolation of enriched mixtures of the most stable cis-isomers.
A Carbaboranylmercuric Salt Catalyzed Reaction; Highly Regioselective Cycloisomerization of 1,3-Dienes
The combination of carbaboranylmercuric chloride (new type of bulky Lewis acid) and silver triflate efficiently catalyzes cycloisomerization of 1, 3-dienes at room temperature. The catalytic system gives allyl-substituted azacycles and cycloalkanes in excellent yields with high to complete regioselectivity.