title: Salicylato titanocene complexes as cooperative organometallic Lewis acid and Brønsted acid catalysts for three-component mannich reactions.
abstract: A binary acid system has been developed that features an air-stable organometallic precursor, titanocene dichloride, and simple organic cooperative Brønsted acids, which allowed for mild and highly efficient Mannich reactions of both aryl and alkyl ketones with excellent yields and satisfactory diastereoselectivity. Mechanistic studies, including (1) H NMR titration, X-ray structure analyses as well as isolation of catalytically active species, elucidated the dramatic synergistic effects of this new binary acid system.
authors: Key Laboratory of Applied Surface and Colloid Chemistry, MOE, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062 (P.R. China), Fax: (+86) 29-81530727.
authors: Ya
authors: Y
authors: Wu
authors: Chun
authors: C
authors: Chen
authors: Gai
authors: G
authors: Jia
authors: Xuyang
authors: X
authors: Zhu
authors: Huaming
authors: H
authors: Sun
authors: Guofang
authors: G
authors: Zhang
authors: Weiqiang
authors: W
authors: Zhang
authors: Ziwei
authors: Z
authors: Gao
keywords: Brønsted acids; CC coupling; cooperative catalysis; organometallic Lewis acid; salicylic acid