Passerini Reactions on Biocatalytically Derived Chiral Azetidines

Abstract

Abstract:The purpose of this study was to explore a series of Passerini reactions on a biocatalytically derived enantiopure azetidine-2-carboxyaldehyde in order to obtain, in a diastereoselective manner, polyfunctionalised derivatives having the potential to be cyclized to chiral bridged bicyclic nitrogen heterocycles. While diastereoselectivity was poor under classical Passerini conditions, a significant increase of diastereoselectivity (up to 76:24) was gained by the use of zinc bromide as promoter. The methodology has a broad scope and yields are always good.

Transition Metal and Inner Transition Metal Catalyzed Amide Derivatives Formation through Isocyanide Chemistry

“…49 Riva and co-workers explored the ZnBr 2 -promoted diastereoselective (up to 76:24) Passerini reaction of enantiopure azetidine-2-carbaldehyde. 50 A ZnCl 2 -catalyzed diastereoselective Joullié-Ugi threecomponent reaction of 2H-azirines, isocyanides, and carboxylic acids has been reported. 51 Using this method, functionalized N-acylaziridine-2-carboxamide derivatives were prepared in up to 82% isolated yields and up to 99% diastereoselectivity.…”

Zinc(ii)-mediated diastereoselective Passerini reactions of biocatalytically desymmetrised renewable inputs

“…This fruitful combination 10 was first proposed by Ostaszewski and coworkers 11 and since then used by various research groups, [12][13][14][15][16][17] including ours. [18][19][20][21][22][23][24][25][26][27][28][29] From a green chemistry perspective, while the use of renewable starting materials, the implementation of MCRs 30 and the practice of biocatalysis [31][32][33] all represent desirable approaches, the union of these three in a single integrated, general strategy can boost their individual beneficial impact on sustainable synthesis. In this paper, we provide an example of this strategy, which makes use of biocatalysis as well as the Passerini multicomponent reaction for the stereoselective transformation of BHMTHF (3) into chiral, relatively complex, depsipeptides.…”

Stereodivergent access to all four stereoisomers of chiral tetrahydrobenzo[f][1,4]oxazepines, through highly diastereoselective multicomponent Ugi–Joullié reaction

“…Recently, some examples of diastereoselective Passerini reactions on chiral enantiopure aldehydes or ketones have been reported, [11][12][13][14][15][16] but the related Ugi reaction is more problematic, not only because of the low diastereoselectivity typically achieved, but also for the easy racemization of aldehydes with astereogenic centres. 17 Better results have been accomplished with the so called Ugi-Joullié reaction.…”