Copper(I) complexes of a new participative triphosphane ligand (2 H ) have been prepared and structurally characterized, in particular [Cu(2 H )I] and [Cu(2)]2. Hydrogenation of the latter species afforded the trimetallic hydride species [Cu3(2)2(µ-H)] or in the presence of BEt3, [Cu(2 H )(HBEt3)]. Their formation evidences transient formation of [Cu(2 H )H] formed by hydrogenolysis of the Cu-N bond of [Cu(2)]2. [Cu(2 H )(HBEt3)] behaves like a hydride complex and inserts CO2 to yield the formate product [Cu(2 H )(O2CH)]. QTAIM analysis of the Cu-H-BEt3 interaction indicates a hydride complex stabilized by the Lewis acid BEt3.

Copper(I) complexes of a new participative triphosphane ligand (<b>2^H</b>) have been prepared and structurally characterized, in particular [Cu(<b>2^H</b>)I] and [Cu(<b>2</b>)]₂. Hydrogenation of the latter species afforded the trimetallic hydride species [Cu₃(<b>2</b>)₂(µ-H)] or in the presence of BEt₃, [Cu(<b>2^H</b>)(HBEt₃)]. Their formation evidences transient formation of [Cu(<b>2^H</b>)H] formed by hydrogenolysis of the Cu‒<br>N bond of [Cu(<b>2</b>)]₂. [Cu(<b>2^H</b>)(HBEt₃)] behaves like a hydride complex and inserts CO₂ to yield the formate product [Cu(<b>2^H</b>)(O₂CH)].<br>

Easily accessible via a simple esterification of alcohols with formic acid, alkyl formates are used as a novel class of transfer hydroalkylation reagents, CO2 acting as a traceless linker. As a proof‐of‐concept, their reactivity in the transfer hydroalkylation of imines is investigated, using a ruthenium‐based catalyst and LiI as promoter to cleave the C−O σ‐bond of the formate scaffold. Providing tertiary amines, the reaction displays a divergent regioselectivity compared to previously reported transfer hydroalkylation strategies.