Tantalum Catalyzed Hydroaminoalkylation for the Synthesis of α- and β‑Substituted <i>N</i>‑Heterocycles

Unprotected secondary amines are directly alkylated by C–H functionalization adjacent to nitrogen, thereby opening new routes toward the synthesis of α- and β-alkylated <i>N</i>-heterocycles. α-Alkylated piperidine, piperazine, and azepane products are prepared from heterocycles and alkenes in an atom-economic reaction with excellent regio- and diastereoselectivity. β-Alkylated <i>N</i>-heterocycles are synthesized via a scalable one-pot alkylation/cyclization procedure generating 3-methylated azetidines, pyrrolidines, and piperidines

Development of Versatile Sulfone Electrophiles for Suzuki–Miyaura Cross-Coupling Reactions

The development of fluorinated sulfone derivatives as versatile electrophiles for Suzuki–Miyaura cross-coupling reactions is described. Introducing electron-withdrawing groups on the aryl ring of the sulfone facilitates the Pd-catalyzed activation of C–SO₂ bonds. Cross-coupling reactions with fluorinated sulfone electrophiles are reported, leading to a variety of multiply arylated products in good yields. The reactivity of this unusual electrophile is benchmarked versus common electrophiles and its use in iterative cross-couplings for concise synthesis of biologically active molecules is described

Tantalum Catalyzed Hydroaminoalkylation for the Synthesis of α- and β‑Substituted <i>N</i>‑Heterocycles

Unprotected secondary amines are directly alkylated by C–H functionalization adjacent to nitrogen, thereby opening new routes toward the synthesis of α- and β-alkylated <i>N</i>-heterocycles. α-Alkylated piperidine, piperazine, and azepane products are prepared from heterocycles and alkenes in an atom-economic reaction with excellent regio- and diastereoselectivity. β-Alkylated <i>N</i>-heterocycles are synthesized via a scalable one-pot alkylation/cyclization procedure generating 3-methylated azetidines, pyrrolidines, and piperidines

Tantalum Catalyzed Hydroaminoalkylation for the Synthesis of α- and β‑Substituted <i>N</i>‑Heterocycles

Unprotected secondary amines are directly alkylated by C–H functionalization adjacent to nitrogen, thereby opening new routes toward the synthesis of α- and β-alkylated <i>N</i>-heterocycles. α-Alkylated piperidine, piperazine, and azepane products are prepared from heterocycles and alkenes in an atom-economic reaction with excellent regio- and diastereoselectivity. β-Alkylated <i>N</i>-heterocycles are synthesized via a scalable one-pot alkylation/cyclization procedure generating 3-methylated azetidines, pyrrolidines, and piperidines

Bis(amidate)bis(amido) Titanium Complex: A Regioselective Intermolecular Alkyne Hydroamination Catalyst

An efficient and selective bis­(amidate)­bis­(amido) titanium precatalyst for the anti-Markovnikov hydroamination of alkynes is reported. Hydroamination of terminal and internal alkynes with primary alkylamines, arylamines, and hydrazines is promoted by 5–10 mol % of Ti catalyst. Various functional groups are tolerated including esters, protected alcohols, and imines. The in situ generated complex shows comparable catalytic activity, demonstrating its synthetic versatility for benchtop application. Applications of this catalyst for the synthesis of amino alcohols and a one-pot procedure for indole synthesis are described. A mechanistic proposal that invokes turnover-limiting protonolysis is presented to rationalize the observed regioselectivities