Three-component reductive conjugate addition/aldol tandem reaction enabled by nickel/photoredox dual catalysis

Abstract

A three-component reductive cross-coupling of aryl halides, aldehydes, and alkenes by nickel/photoredox dual catalysis is disclosed. Key to success for this tandem transformation is to identify α-silylamine as a unique...

Nickel/photoredox dual-catalyzed reductive cross-coupling of aryl halides and aldehydes

“…16 In this process, α-silylamine was identified as a uniquely efficient organic reductant. Based on our ongoing interest in photoredoxassisted reductive cross-coupling, 16,17 we herein reported a photoredox/nickel-catalyzed reductive coupling of aryl halides with aldehydes to prepare silyl-protected secondary alcohols using α-silylamines as very mild, stable, and readily available reductants (ease to prepare: a one-step S N 2 reaction from secondary amines and TMSCH 2 X) (Scheme 1c). This organic reductant-mediated carbonyl-reductive cross-coupling features extremely mild conditions with no need for any additives 9,[11][12][13] (e.g.…”

“…13 Recently, our lab has demonstrated a conjugate reductive coupling of aryl halides, aldehydes, and alkenes via a nickel/photoredox dual catalysis. 16 In this process, α-silylamine was identified as a uniquely efficient organic reductant. Based on our ongoing interest in photoredox-assisted reductive cross-coupling, 16,17 we herein reported a photoredox/nickel-catalyzed reductive coupling of aryl halides with aldehydes to prepare silyl-protected secondary alcohols using α-silylamines as very mild, stable, and readily available reductants (ease to prepare: a one-step S N 2 reaction from secondary amines and TMSCH 2 X) (Scheme 1c).…”

Nickel/Photoredox Dual-Catalyzed Regiodivergent Aminoalkylation of Unactivated Alkyl Halides

“…Moreover, by harnessing a NiH chain-walking event, the migratory hydroaminoalkylation of unactivated alkenes has also been disclosed . As a potent organic reductant, α-silylamine was also used in a catalytic reductive conjugate addition/aldol sequence . Based on our previous works and in line with the synthetic importance of alkylamines, we further seek to investigate the cross-coupling of tertiary alkyl amines and unactivated alkyl halides to forge new C­(sp 3 )–C­(sp 3 ) bonds in a highly site-controllable way.…”

TMSOTf-Catalyzed [4 + 2] Annulation of Ynamides and β-(2-Aminophenyl)-α,β-ynones for the Synthesis 2-Aminoquinolines

“…Then the nucleophilic N-attack of ynone 1 on keteniminium ion A generates the vinyl–silicon intermediate B , which undergoes protodesilication to achieve enamine intermediate C . Subsequently, an intramolecular cyclization of TMSOTf-activated ynone D by a conjugate addition reaction occurs to produce intermediate E . Protodesilication of intermediate E is followed by enol/ketone tautomerism leading to intermediate 3 .…”