Copper-catalyzed transfer methylenation via C(sp³)–C(sp³) bond cleavage of alcohols

Abstract

Transfer hydrogenation between alcohols and carbonyl compounds via C-H bond cleavage is well known, whereas transfer hydrocarbylation remains a challenge due to the unactivated C-C bond cleavage. Herein, we disclose...

Pd-Catalyzed Formal [2 + 2]-Retrocyclization of Cyclobutanols via 2-Fold Csp3–Csp3 Bond Cleavage

“…The higher bond enthalpy of unstrained Csp 3 –Csp 3 linkages compared to those present in strained molecules renders the cleavage of the first ones a challenging goal. − One of the approaches to achieve β-alkyl elimination in unstrained substrates through TM-catalysis relies on the introduction of auxiliary coordinating or chelating groups within the molecular skeleton of the substrate. Thus, a range of alcohols bearing a coordinating moiety conveniently located in its structure (pyridyl, , pyridyl- N -oxide, ketone, , azide, or allyl groups) have been successfully derivatized through Csp 3 –Csp 3 cleavage (Scheme , b). Other chelating groups like 8-aminoquinoline have also been reported to assist β-alkyl elimination in Pd-mediated or catalyzed systems. , …”

Copper-Catalyzed Aza-Benzyl Transfer Michael Addition via C–C Bond Cleavage

“…Recently, we developed the methylene borrowing reaction between alcohols and ketones under transition-metal-free conditions, although the necessity of stoichiometric base and harsh reaction conditions significantly limited the substrate scope. Inspired by our previous works on the transition-metal-catalyzed β-carbon elimination of alcohols and catalytic methylene migration and transfer, we designed the transition-metal-catalyzed aza-benzyl transfer Michael addition via C–C bond cleavage. The alkyl–metal species, generated from the tertiary alcohol ( 1 ) via catalytic C–C bond cleavage, add to α,β-unsaturated carbonyl compounds to afford the Michael adducts.…”