Chemoselective Acylation of Primary Amines in the Presence of Secondary Amines with Acyl Cyanides. Highly Efficient Methods for the Synthesis of Spermidine and Spermine Alkaloid
Acyl cyanides are highly useful reagents for the chemoselective acylation of primary amines in the presence of secondary amines. The reaction provides the versatile method for the short-step synthesis of various naturally occurring polyamines.
Ruthenium-Catalyzed Oxidations for Selective Syntheses of Ketones and Acyl Cyanides. Selective Acylation of Amino Compounds with Acyl Cyanides
作者:Shun-Ichi Murahashi、Takeshi Naota
DOI:10.1055/s-1993-25877
日期:——
Oxidation of alcohols to the corresponding carbonyl compounds with tert-butyl hydroperoxide in the presence of dichlorotris(triphenylphosphine)ruthenium catalyst gives the corresponding carbonyl compounds with high efficiency. This method can be applied to the oxidation of cyanohydrins to give acyl cyanides which are versatile synthetic intermediates. Acylation of amino compounds with acyl cyanides thus obtained proceeds chemoselectively. Thus, the reaction of amino alcohols with acyl cyanides gives N-acylated products exclusively. In the similar N-acylation of polyamines primary amines are selectively acylated in the presence of secondary amines. These reactions are highly useful for the synthesis of spermidine and spermine alkaloids such as spermidine siderophores. Dimeric cyclocoupling reaction of diacyl cyanides such as iso- and terephthaloyl cyanides with polyamines can be performed under the similar reaction conditions to give the corresponding polyazamacrocycles with high efficiency.
N-acylation reaction offers an opportunity to develop an efficient synthesis of amide group-containing molecules. We found that N-acyl carbazoles showed remarkable selectivity in transamidation. Sterically less hindered primary amines are selectively acylated with N-acyl carbazoles without any additives. Various functional groups such as alcohol, phenol, indole, and aniline moieties are tolerated under mild conditions. The synthetic utility was displayed in one-pot synthesis of an N-acyl polyamine natural product. The terminal amines of spermidine were selectively benzoylated with N-benzoyl carbazole, followed by acetylation reaction accomplished the total synthesis in a highly efficient manner.