Iridium complexes modified by PhanePhos catalyze the 2-propanol-mediated reductive coupling of diverse 1,1-disubstituted allenes 1a-1u with fluoral hydrate 2a to form CF 3-substituted secondary alcohols 3a-3u that incorporate acyclic quaternary carbon-containing stereodiads. By exploiting concentration-dependent stereoselectivity effects related to the interconversion of kinetic (Z)-and thermodynamic (E)-σ-allyliridium isomers, adducts 3a-3u are formed with complete levels of branched regioselectivity and high levels of anti-diastereoand enantioselectivity. The utility of this method for construction of CF 3-oxetanes and CF 3-azetidines is illustrated by the formation of 4a and 6a, respectively. Studies of the reaction mechanism aimed at illuminating the singular effectiveness of PhanePhos as a supporting ligand in this and related transformations have led to the identification of a chromatographically stable cyclometallated iridium-(R)-PhanePhos complex Ir-PP-I that is catalytically competent for allene-fluoral reductive coupling and previously reported transfer hydrogenative CC couplings of dienes or CF 3-allenes with methanol. Deuterium labelling studies, reaction progress kinetic analysis (RPKA) and computational studies corroborate a catalytic mechanism involving rapid allene hydrometalation followed by turnover-limiting carbonyl addition. A computationally determined stereochemical

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The first catalytic enantioselective ruthenium-catalyzed carbonyl reductive couplings of allene pronucleophiles is described. Using an iodide-modified ruthenium-BINAP-catalyst and O-benzhydryl alkoxyallene 1a, carbonyl (α-alkoxy)­allylation occurs from the alcohol or aldehyde oxidation level to form enantiomerically enriched syn-sec,tert-diols. Internal chelation directs intervention of (Z)-σ-alkoxyallylruthenium isomers, which engage in stereospecific carbonyl addition.

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In the presence of a neutral dppf-modified iridium catalyst and CsCO, linear allylic acetates react with primary amines to form products of hydroamination with complete 1,3-regioselectivity. The collective data, including deuterium labeling studies, corroborate a catalytic mechanism involving rapid, reversible acetate-directed aminoiridation with inner-sphere/outer-sphere crossover followed by turnover-limiting proto-demetalation mediated by amine.