Iridium-Catalyzed Enantioselective Allenylic Cyanomethylation.

The poor acidity of acetonitrile restricted its utility as a C2 synthon of a cyanomethyl group for incorporation into organic compounds. We now employed a 2-azido allylic alcohol as an acetonitrile enolate surrogate for the first enantioselective allenylic cyanomethylation. This mild and base-free protocol utilizes cooperative iridium and Lewis acid catalysis for the activation of branched allenylic alcohols to deliver α-allenylic acetonitriles in moderate to good yields with excellent enantioselectivity.

Correction: Hydroxy-directed iridium-catalyzed enantioselective formal β-C(sp)-H allylic alkylation of α,β-unsaturated carbonyls.

[This corrects the article DOI: 10.1039/D2SC03966D.].

Hydroxy-directed iridium-catalyzed enantioselective formal β-C(sp)-H allylic alkylation of α,β-unsaturated carbonyls.

Hydroxy-directed iridium-catalyzed enantioselective formal β-C(sp)-H allylic alkylation of kojic acid and structurally related α,β-unsaturated carbonyl compounds is developed. This reaction, catalyzed by an Ir(i)/(,olefin) complex, utilizes the nucleophilic character of α-hydroxy α,β-unsaturated carbonyls, to introduce an allyl group at its β-position in a branched-selective manner in good to excellent yield with uniformly high enantioselectivity (up to >99.9 : 0.

Iridium-Catalyzed Enantioselective and Chemodivergent Allenylic Alkylation of Vinyl Azides for the Synthesis of α-Allenylic Amides and Ketones.

The first enantioselective synthesis of α-allenylic amides and ketones through allenylic alkylation of vinyl azides is reported. In these chemodivergent reactions, cooperatively catalyzed by a Ir /(phosphoramidite,olefin) complex and Sc(OTf) , vinyl azides act as the surrogate for both amide enolates and ketone enolates. The desiccant (molecular sieves) plays a crucial role in controlling the chemodivergency of this enantioconvergent and regioselective reaction: Under otherwise identical reaction conditions, the presence of the desiccant led to α-allenylic amides, while its absence resulted in α-allenylic ketones.

Iridium-Catalyzed Enantioselective α-Allylic Alkylation of Amides Using Vinyl Azide as Amide Enolate Surrogate.

Among the unstabilized enolates used as nucleophiles in iridium-catalyzed asymmetric allylic alkylation reactions, amide enolates are the least explored. Vinyl azides are now employed as amide enolate surrogates in Ir-catalyzed asymmetric allylic alkylation with branched allylic alcohols as the allylic electrophile. Competing reaction pathways are suppressed through the systematic tuning of the steric and electronic properties of vinyl azide to effect the α-allylic alkylation of secondary acetamides with high atom economy, exclusive branched selectivity, and mostly excellent enantioselectivity.