Catalytic intramolecular hydroamination of substituted aminoallenes by chiral titanium amino-alcohol complexes

Intramolecular hydroamination of aminoallenes is catalyzed by titanium complexes with a number of chiral amino alcohols. The ring-closing reaction of hepta-4,5-dienylamine at 110 degreesC with 5 mol % catalyst gives a mixture of 6-ethyl-2,3,4,5-tetrahydropyridine (14-33%) and both Z- and E-2-propenylpyrrolidine (67-86%). However, the ring-closing reaction of 6-methylhepta-4,5-dienylamine at 135 degreesC with 5 mol % catalyst gives exclusively 2-(2-methylpropenyl)pyrrolidine. The pyrrolidine products are obtained with enantiomeric excesses up to 16%.