Asymmetric Strecker Reactions

A study on the induction of stereoselectivity in the Strecker synthesis of basic amino acid-derived α-amino nitriles

“…First, we studied the replacement of ZnCl 2 by chiral organocatalysts in the synthesis of 9a. Among the diverse organocatalysts developed for enantioselective Strecker reactions, 6,8,11,12 we tried the commercial thiourea 12 ( Fig. 1), developed by the Jacobsen group.…”

“…[2][3][4] During the last years, attention has mainly been focused on the stereocontrol in the Strecker reaction, by using chiral auxiliaries 2,3,5,6 and, more recently, chiral catalysts. [5][6][7][8][9][10][11][12] -Amino nitriles are versatile intermediates for the synthesis of multiple building blocks. 5,6 In particular, -amino acid-derived amino nitriles have shown high potential for molecular diversity generation.…”

“…[5][6][7][8][9][10][11][12] -Amino nitriles are versatile intermediates for the synthesis of multiple building blocks. 5,6 In particular, -amino acid-derived amino nitriles have shown high potential for molecular diversity generation. 13 Thus, we have shown their utility in the synthesis of pseudopeptides, 14,15 and diverse chiral heterocyclic compounds.…”

Recent advances on asymmetric Strecker reactions

“…After the reaction, the auxiliary group must be cleaved from the product, and the chiral auxiliaries recovered and reused. The catalytic asymmetric Strecker reaction [3][4][5][6][7][8][9] has proved to be a simple and efficient method for the synthesis of optically pure α-amino acid derivatives. 10 Its development has been extremely fast since the first report of such a reaction appeared in 1996.…”

Scalable organocatalytic asymmetric Strecker reactions catalysed by a chiral cyanide generator

“…The Strecker synthesis 3 -the reaction of an imine or imine equivalent with hydrogen cyanide, followed by nitrile hydrolysis-is a standard method for producing a-amino acids [4][5][6][7] . Although there is already a number of useful catalytic asymmetric variants showing high catalyst efficiency [8][9][10][11][12][13][14][15][16][17] , the limited utility of existing catalytic methods may be due to several important factors, including the relatively complex and precious nature of the catalysts, and the use of hazardous cyanide sources (for example, HCN, acetone cyanohydrin or trimethylsilyl cyanide) in super-stoichiometric amounts, preventing their practical application to large-scale processes. Moreover, it has often been observed that direct hydrolysis of optically active a-aminonitriles can result in deterioration of optical purity of the amino acid products 18 .…”