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Synthesis of Pyrrolidines by a Csp 3 ‐Csp 3 /Csp 3 ‐ N Transition‐Metal‐Free Domino Reaction of Boronic Acids with γ‐Azido‐ N ‐Tosylhydrazones
Author(s) -
Florentino Lucía,
López Lucía,
Barroso Raquel,
Cabal MaríaPaz,
Valdés Carlos
Publication year - 2021
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202010528
Subject(s) - chemistry , cyclohexanone , intramolecular force , intermolecular force , azide , diastereomer , transition state , catalysis , combinatorial chemistry , organic chemistry , molecule
The reaction between γ‐azido‐ N ‐tosylhydrazones and boronic acids leads to the obtention of 2,2‐disubstituted pyrrolidines in a domino process that includes 1) diazoalkane formation, 2) intermolecular carboborylation of the diazocompound, and 3) intramolecular carborylation of the azide, and comprises the formation of a Csp 3 −Csp 3 and a Csp 3 −N bonds on the same carbon atom. The reaction proceeds without the need of any transition‐metal catalyst under microwave activation and features wide scope in both reaction partners. It can be applied to both alkyl and arylboronic acids with equal efficiency. With N ‐tosylhydrazones derived from 2‐(2‐azidoethyl)‐cyclopentanone and cyclohexanone the reactions are highly diastereoselective leading to the cis ‐fused bicyclic systems as unique diastereoisomers. The scope of the process is illustrated by over sixty examples, including scaffolds present in natural alkaloids, and the mechanistic proposal is suppported by DFT‐based computations.