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A Dinickel Catalyzed Cyclopropanation without the Formation of a Metal Carbene Intermediate
Author(s) -
Maity Arnab K.,
Kalb Annah E.,
Zeller Matthias,
Uyeda Christopher
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.202011602
Subject(s) - cyclopropanation , carbene , cyclopropane , chemistry , catalysis , regioselectivity , medicinal chemistry , diene , photochemistry , stereochemistry , organic chemistry , ring (chemistry) , natural rubber
(NDI)Ni 2 catalysts (NDI=naphthyridine‐diimine) promote cyclopropanation reactions of 1,3‐dienes using (Me 3 Si)CHN 2 . Mechanistic studies reveal that a metal carbene intermediate is not part of the catalytic cycle. The (NDI)Ni 2 (CHSiMe 3 ) complex was independently synthesized and found to be unreactive toward dienes. Based on DFT models, we propose an alternative mechanism that begins with a Ni 2 ‐mediated coupling of (Me 3 Si)CHN 2 and the diene. N 2 extrusion followed by radical C−C bond formation generates the cyclopropane product. This model reproduces the experimentally observed regioselectivity and diastereoselectivity of the reaction.