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2.9.2.1.3.3 Bis(η5-cyclopentadienyl)dimethyltitanium(IV) (Petasis Reagent) Mediated Intramolecular Hydroamination/Cyclization of Alkynamines

DOI: 10.1055/sos-SD-222-00230

Mondal, M.; Bora, U.Science of Synthesis: Metal-Catalyzed Cyclization Reactions, (20162403.

In the presence of 5 mol% of the Petasis reagent [TiMe2(Cp)2; bis(η5-cyclopentadienyl)dimethyltitanium(IV)} the intramolecular hydroamination/cyclization of alkynamines proceeds smoothly to give five-membered cyclic imines within 4–6 hours in toluene at 100–110 °C. Subsequent reduction of the cyclic imine with zinc-modified sodium cyanoborohydride in tetrahydrofuran at room temperature provides efficient access to pyrrolidines 42 (Scheme 20).[‌254‌]

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