Titanium-mediated reductive cross-coupling reactions of imines with terminal alkynes: An efficient route for the synthesis of stereodefined allylic amines

• Main Authors: Kebin Mao, Guoqin Fan, Yuanhong Liu, Shi Li, Xu You, Dan Liu
• Format: Article
• Language: English
• Published: Beilstein-Institut 2013-03-01
• Series: Beilstein Journal of Organic Chemistry
• Subjects: allylic amine; azatitanacyclopentene; reductive cross-coupling; regioselectivity; terminal alkyne; titanium-imine complex
• Online Access: https://doi.org/10.3762/bjoc.9.69
• ISSN: 1860-5397

Low-valency titanium species, generated in situ by using Ti(OiPr)4/2 c-C5H9MgCl reagent, react with imines to give a titanium-imine complex that can couple with terminal alkynes to provide azatitanacyclopentenes with excellent regioselectivity. Stereodefined allylic amines are obtained in good yields after hydrolysis or iodonolysis of the corresponding azatitanacyclopentenes. When ethynylcyclopropane is used as the coupling partner to react with imines in this reaction, the initially generated allylic amine undergoes an unexpected 1,3-amino migration on silica gel during the column chromatography.