Corey-Link reaction

This reaction was first reported by Corey and T.ink in 1992. It is an enantioselective synthesis of a -amino acids by means of the asymmetric reduction of trichloromethyl ketones from catechoiborane in the presence of either (/ )- or (5)-oxazaborolidine, followed by the treatment of the resulting alcohols with base and sodium azide and subsequently the reductive conversion of the azido group into an amino group. Therefore, this reaction is generally known as the Corey-Link reaction. Occasionally, it is also referred to as the Corey-Link amino acid synthesis, Corey-Link procedure, etc. 

Other references related to the Corey-Link reaction are cited in the literature. ... 

In many of the precedent reactions, pyridines are inert, and activation of this fundamental heterocycle remains problematic. To overcome this problem, more powerful activating agents have been tested. For instance, Corey explored the use of triflic anhydride (35) as an efficient method to link a variety of nucleophiles to the pyridine y-position (see 34, Scheme 6) [49]. This reaction in the presence of isocyanides affords a mixture of the a-and y-carbamoylated dihydropyridines 245 and 246 together with the corresponding oxidized products 245 and 246, respectively, in low overall yield (Scheme 36a). A major problem here is the massive degradation of the isocyanide under these rather drastic conditions. Trifiuoroacetic... 

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