Amination of allylic alcohols is facilitated via cooperative catalysis. Catalytic Ti(O- i-Pr) is shown to dramatically increase the rate of nickel-catalyzed allylic amination, and mechanistic experiments confirm activation of the allylic alcohol by titanium. Aminations of primary and secondary allylic alcohols are demonstrated with a variety of amine nucleophiles. Diene-containing substrates also cyclize onto the nickel allyl intermediate prior to amination, generating carbocyclic amine products. This tandem process is only achieved under our cooperative catalytic system.

We report an unprecedented boron-templated dimerization of allylic alcohols that generates a 1,3-diol product with two stereogenic centers in high yield and diastereoselectivity. This acid-catalyzed reaction is achieved via in situ formation of a boronic ester intermediate that facilitates selective cyclization and formation of a cyclic boronic ester product. High yields are observed with a variety of allylic alcohols, and mechanistic studies confirm the role of boron as a template for the reaction.

We report the synthesis of a 2-phosphinoimidazole-derived bimetallic Rh(II) complex that enables intramolecular allene hydroamination to form 7- to 10-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of various N-heterocycles. Macrocyclizations that form 11- to 15-member N-heterocycles are also demonstrated. Mechanistic studies suggest that the reaction proceeds via reversible allene insertion with a Rh-hydride followed by C–N bond-forming reductive elimination. We hypothesize that the reactivity observed with our catalyst vs monometallic Rh complexes is derived from the bimetallic nature of our complex.

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We report the synthesis of a bimetallic Rh(I) complex containing a bridging CO ligand that facilitates Rh–Rh bond formation. This bimetallic complex enables intramolecular allene hydroamination to form seven to ten-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of a variety of N-heterocycles in good to excellent yields. Macrocyclization reactions that form eleven to fifteen-membered heterocycles are also demonstrated. Mechanistic studies show that the reaction likely proceeds via catalyst protonation by trifluoroacetic acid, followed by reversible allene insertion and C–N bond-forming reductive elimination. The difference in product selectivity observed with our bimetallic catalyst vs monometallic Rh complexes may result from cooperativity between the two metals.

We report the synthesis of a bimetallic Rh(I) complex containing a bridging CO ligand that facilitates Rh–Rh bond formation. This bimetallic complex enables intramolecular allene hydroamination to form seven to ten-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of a variety of N-heterocycles in good to excellent yields. Macrocyclization reactions that form eleven to fifteen-membered heterocycles are also demonstrated. Mechanistic studies show that the reaction likely proceeds via catalyst protonation by trifluoroacetic acid, followed by reversible allene insertion and C–N bond-forming reductive elimination. The difference in product selectivity observed with our bimetallic catalyst vs monometallic Rh complexes may result from cooperativity between the two metals.

We report the synthesis of a bimetallic Rh(I) complex containing a bridging CO ligand that facilitates Rh–Rh bond formation. This bimetallic complex enables intramolecular allene hydroamination to form seven to ten-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of a variety of N-heterocycles in good to excellent yields. Macrocyclization reactions that form eleven to fifteen-membered heterocycles are also demonstrated. Mechanistic studies show that the reaction likely proceeds via catalyst protonation by trifluoroacetic acid, followed by reversible allene insertion and C–N bond-forming reductive elimination. The difference in product selectivity observed with our bimetallic catalyst vs monometallic Rh complexes may result from cooperativity between the two metals.

We report the synthesis of a bimetallic Rh(I) complex containing a bridging CO ligand that facilitates Rh–Rh bond formation. This bimetallic complex enables intramolecular allene hydroamination to form seven to ten-member rings in high yield. Monometallic Rh complexes, in contrast, fail to achieve any product formation. We demonstrate a broad substrate scope for formation of a variety of N-heterocycles in good to excellent yields. Macrocyclization reactions that form eleven to fifteen-membered heterocycles are also demonstrated. Mechanistic studies show that the reaction likely proceeds via catalyst protonation by trifluoroacetic acid, followed by reversible allene insertion and C–N bond-forming reductive elimination. The difference in product selectivity observed with our bimetallic catalyst vs monometallic Rh complexes may result from cooperativity between the two metals.