Chirality 2009-02-01

Highly enantioselective addition of terminal alkynes to aldehydes catalyzed by a new chiral beta-sulfonamide alcohol/Ti(OiPr)4/Et2Zn/R3N catalyst system.

Li Qiu, Quan Wang, Li Lin, Xiaodong Liu, Xianxing Jiang, Qingyang Zhao, Guowen Hu, Rui Wang

Index: Chirality 21(2) , 316-23, (2009)

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Abstract

A new catalytic system, generated from the readily available and inexpensive beta-sulfonamide alcohol L*, Ti(O(i)Pr)(4), Et(2)Zn, and tertiary amine base (R(3)N), effectively catalyzes the enantioselective addition of various terminal alkynes including some quite challenging alkynes to aldehydes in good yields and excellent enantioselectivities. Up to 96% yield and >99% enantioselectivity were achieved with the use of N,N-diisoproylethylamine (DIPEA) as an additive in this asymmetric addition.(c) 2008 Wiley-Liss, Inc.