Open AccessTwo Copper-Carbenes from One Diazo Compound
Author(s) -
M. Ángeles Alvarez,
María Besora,
F. Molina,
Feliu Maseras,
Tomás R. Belderraín,
Pedro J. Pérez
Publication year - 2021
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.1c01483
Subject(s) - carbene , diazo , chemistry , decarbonylation , intramolecular force , cyclopropanation , ligand (biochemistry) , carbon monoxide , medicinal chemistry , copper , photochemistry , stereochemistry , organic chemistry , catalysis , biochemistry , receptor
Many transition-metal complexes ML n decompose diazo compounds N 2 ═CR 1 R 2 generating metal-carbenes L n M═CR 1 R 2 which transfer the carbene group to other substrates, constituting an important tool in organic synthesis. All previous reports have shown that the CR 1 R 2 fragment at the metal-carbene remains intact from the parent diazo compound. Herein we report the detection and isolation of a monosubstituted copper carbene where the CR 1 R 2 ligand has undergone a modification from the initial diazo reagent. When Tp Ms Cu(THF) (Tp Ms = hydrotris(3-mesityl)pyrazolylborate ligand) was reacted with N,N -diethyl diazoacetamide [N 2 ═C(H)(CONEt 2 )], the stable copper carbene Tp Ms Cu═C(H)(NEt 2 ) was isolated, resulting from a decarbonylation process, with carbon monoxide being trapped as Tp Ms Cu(CO). The simultaneous observation of products derived from the intramolecular carbene insertion reaction into C-H bonds demonstrates that the expected Tp Ms Cu═C(H)(CONEt 2 ) complex is also formed. Experimental data, DFT calculations, and microkinetic models allow us to propose that the latter undergoes CO loss en route to the former.