Organophotoredox/Ni-Cocatalyzed Allylation of Allenes: Regio-, and Diastereoselective Access to Homoallylic Alcohols

A dual organophotoredox/nickel-catalyzed reductive coupling of allenes with aldehydes has been developed for the rapid assembly of anti-homoallylic alcohols with high levels of regioselectivities (>20:1), and diastereoselectivities (up to >20:1) and yields (up to 91%). The allylation was realized through a crucial π-allylnickel intermediate which was obtained via insertion of allenes with a Ni−H intermediate. Moreover, γ,γ-disubstituted homoallylic alcohols with a quaternary stereocenter can also be prepared by this protocol.

Confronting the Challenging Asymmetric Addition of Vinyl Arene Pronucleophiles into Ketones: Ligand-Controlled Regiodivergent Processes Through a Dearomatized Allyl-Cu Species

The selective reductive coupling of vinyl arenes and ketones represents a versatile approach for the rapid construction of enantiomerically enriched tertiary alcohols. Herein, we demonstrate a CuH-catalyzed regiodivergent coupling of vinyl arenes and ketones, in which the selectivity is controlled by the ancillary ligand. This approach leverages an in situ generated benzyl- or dearomatized allyl-Cu intermediate, yielding either the dearomatized or exocyclic addition products, respectively. The method exhibits excellent regio-, diastereo- and enantioselectivity, and tolerates a range of common functional groups and heterocycles. Computational studies suggest that the regio- and enantioselectivity are controlled by the ancillary ligand, while the diastereoselectivity is enforced by steric interactions between the alkyl-Cu intermediate and ketone substrates in a six-membered cyclic transition state.

Electrochemical C–N bond activation for deaminative reductive coupling of Katritzky salts

Electrosynthesis has received great attention among researchers in both academia and industry as an ideal technique to promote single electron reduction without the use of expensive catalysts. In this work, we report the electrochemical reduction of Katritzky salts to alkyl radicals by sacrificing the easily accessible metal anode. This catalyst and electrolyte free platform has broad applicability to single electron transfer chemistry, including fluoroalkenylation, alkynylation and thiolation. The deaminative functionalization is facilitated by the rapid molecular diffusion across microfluidic channels, demonstrating the practicality that outpaces the conventional electrochemistry setups.

Confronting the Challenging Asymmetric Addition of Vinyl Arene Pronucleophiles into Ketones: Ligand-Controlled Regiodivergent Processes Through a Dearomatized Allyl-Cu Species

The selective reductive coupling of vinyl arenes and ketones represents a versatile approach for the rapid construction of enantiomerically enriched tertiary alcohols. Herein, we demonstrate a CuH-catalyzed regiodivergent coupling of vinyl arenes and ketones, in which the selectivity is controlled by the ancillary ligand. This approach leverages an in situ generated benzyl- or dearomatized allyl-Cu intermediate, yielding either the dearomatized or exocyclic addition products, respectively. The method exhibits excellent regio-, diastereo- and enantioselectivity, and tolerates a range of common functional groups and heterocycles. Computational studies suggest that the regio- and enantioselectivity are controlled by the ancillary ligand, while the diastereoselectivity is enforced by steric interactions between the alkyl-Cu intermediate and ketone substrates in a six-membered cyclic transition state.

CO Reductive Oligomerization by a Divalent Thulium Complex and CO2-Induced Functionalization

To date, only a very limited number of complexes based on low-valent main group or f-block elements have allowed the reductive coupling of CO molecules to afford multicarbon oxygenates. Herein, we described the reactivity of the divalent thulium complex [Tm(Cpttt)2] (Cpttt = 1,2,4-tris(tert-butyl)cyclopentadienyl) towards CO, leading to selective CO reductive dimerization and trimerization into ethynediolate (C2) and ketenecarboxylate (C3) complexes, respectively. Quantum chemical (DFT) calculations were performed to shed light on the elementary steps of CO homologation and support a stepwise chain growth from the C2 to the C3 product upon addition of extra CO. The attempted decoordination of the ethynediolate frag-ment by treatment with Me3SiI led to dimerization and rearrangement into a 3,4-dihydroxyfuran-2-one complex. Investiga-tion of the reactivity of the C2 and C3 complexes towards other electrophiles led to unusual functionalization reactions: while the reaction of the ketenecarboxylate C3 complex with electrophiles yielded new multicarbon oxygenated complexes, the addition of CO2 to the ethynediolate C2 complex resulted in the formation of a very reactive intermediate, allowing C–H activation of the toluene solvent. This original intermolecular reactivity corresponds to an unprecedented functionalization of CO-derived ligands, which is induced by CO2.