Chelation- and Non-chelation-Controlled Addition of 2-(Trimethylsilyl)thiazole to .alpha.-Amino Aldehydes: Stereoselective Synthesis of the .beta.-Amino-.alpha.-hydroxy Aldehyde Intermediate for the Preparation of the Human Immunodeficiency Virus Proteinase Inhibitor Ro 31-8959
An efficient stereoselective total synthesis of (–)-galactostatin (–)-1 from N-tert-butoxycarbonyi-2,3-isopropylidene L-serine methyl ester (21% overall yield) is described via thiazole intermediates serving as protected aldehydes; the parallel synthesis of the natural antipole (+)-1 starts from D-serine.
Chelation- and Non-chelation-Controlled Addition of 2-(Trimethylsilyl)thiazole to .alpha.-Amino Aldehydes: Stereoselective Synthesis of the .beta.-Amino-.alpha.-hydroxy Aldehyde Intermediate for the Preparation of the Human Immunodeficiency Virus Proteinase Inhibitor Ro 31-8959
2-Thiazolyl α-Amino Ketones: A New Class of Reactive Intermediates for the Stereocontrolled Synthesis of Unusual Amino Acids
作者:Alessandro Dondoni、Daniela Perrone
DOI:10.1055/s-1993-26021
日期:——
The thiazole-based one carbon homologation of four α-amino acids (L-phenylalanine, L-leucine, L-threonine, and L-serine) to the corresponding α-hydroxy β-amino aldehydes and acids in both configurations at Cα, is described. The methodology involves the following key operations: (i) the conversion of an α-amino ester to a 2-thiazolyl α-amino ketone; (ii) the stereocontrolled reduction of a ketone carbonyl to either syn or anti α,β-amino alcohols; (iii) the aldehyde release from the thiazole ring; (iv) the oxidation of the aldehyde to a carboxylic acid. The methodology was only partially applied to L-phenylglycine because of some limitations in operation (i).