Hydrazoic acid Passerini reaction

In this period, the most important reactions of the isocyanides were the formations of tetrazole derivatives from isocyanides and hydrazoic acid, a process introduced in 1910 by Oliveri-Mandala and Alagna, and then in 1921 Passerini introduced the reaction (P-3CR), which was the first 3-component reaction of the isocyanides. In the 1940s Baker,and later Dewar, proposed mechanisms of the P-3CR. The important role of the intermediate hydrogen bond between the carboxylic acid and the carbonyl compound in suitable solvents was mentioned. ... 

Other acids that have been used in Passerini-type reactions include hydrazoic acid"" and its Lewis acid congenitors, such as A1(N3)3 and TMSN3. In these presence of azide salts the intermediate nitrilium is instead intercepted by azide in a stepwise [3 + 2]-cycloaddition to give the 1,5-... 

Almost simultaneously, the same research group disclosed a [(salen)Al "Me] 43-catalyzed enantioselective Passerini-type reaction of aldehydes, isocyanides, and hydrazoic acid 42, affording a great scope of tetrazole derivatives 44 with good to excellent enantioselectivities (51-95%) (Scheme 8.16) [39]. 

In 2008, Wang and Zhu s group reported the catalytic asymmetric Passerini-type reaction of aldehydes, isocyanides and hydrazoic acid with... 

---