Cu-based carbene involved in a radical process: a new crossover reaction to construct γ-peroxy esters and 1,4-dicarbonyl compounds

Abstract

Through merging Cu-based carbenes in a radical process, a novel crossover reaction has been successfully established, leading to the facile and efficient syntheses of various γ-peroxy esters and 1,4-dicarbonyl compounds. Considering that both Cu-based carbene complexes and radicals are extremely reactive, and therefore exist only in extraordinarily low concentrations, the high selectivity of this coupling reaction is unusual.

Rearrangements of organic peroxides and related processes

“…Peroxy products resulted from the reaction of styrenes 314 , ethyl diazoacetate ( 321 ), and TBHP underwent a Kornblum–DeLaMare rearrangement with formation of γ-ketoester 322 ( Scheme 96 ) [ 376 ].…”

Metal-free C(sp3)–H functionalization: oxidative carbo-oxygenation of α-diazo carbonyls via radical dediazotization

“…On the basis of the above experimental results and literature survey, 20,22 we propose a plausible mechanism for forming products 4 as depicted in Scheme 4. A ligand exchange between PhI(OAc) 2 and NHPI 3 would give intermediate A .…”

“…For instance, Wan and co-workers reported a cobalt-catalyzed oxidative multicomponent coupling of styrenes with diazo compounds and tertiary amines using t -butylhydroperoxide (TBHP) as oxidant, which involved the coupling between cobalt-based carbene radicals with α-aminoalkyl radicals to yield β -ester- γ -amino ketones (Scheme 1a). 20 Enlightened by these interesting results and our ongoing interest in radical chemistry, 21 we envisioned that under the right set of oxidative conditions, suitable diazo compounds could captured phthalimide N -oxyl (PINO) radicals, generated in situ from N -hydroxyphthalimide (NHPI), 22 followed by radical dediazotization toward α-carbonylalkyl radicals, which are then intercepted by α-aminoalkyl radicals to access densely functionalized structures. Herein, we report the successful implementation of this analysis with a novel metal-free C(sp 3 )–H functionalization under one-pot oxidative conditions with use of simple starting materials such as substituted N,N -dimethylanilines 1 , α-diazo carbonyls 2 and N -hydroxyphthalimide 3 .…”

Recent Advances in Radical Difunctionalization of Simple Alkenes

“…In this transformation, the alternative combination of carbene radicals 13 and aminoalkyl radicals 14 ensured the success of this transformation, to afford a series of corresponding products 12 with high chemoselectivity. At almost the same time, an unusual crossover reaction that combined copper‐based carbenes and radical intermediates was also established by the same group (Scheme ) . This reaction could be controlled to provide different products by changing catalyst.…”