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

✍ Scribed by Li Qiu; Quan Wang; Li Lin; Xiaodong Liu; Xianxing Jiang; Qingyang Zhao; Guowen Hu; Rui Wang

Publisher: John Wiley and Sons
Year: 2009
Tongue: English
Weight: 124 KB
Volume: 21
Category: Article
ISSN: 0899-0042
DOI: 10.1002/chir.20583

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✦ Synopsis

Abstract

A new catalytic system, generated from the readily available and inexpensive β‐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. Chirality, 2009. © 2008 Wiley‐Liss, Inc.

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Highly enantioselective alkynylation of aldehydes using a new BINOL/Ti(OiPr)4/chiral sulfonamide catalyst system

✍ Xingshu Li; Gui Lu; Xian Jia; Yinuo Wu; Albert S. C. Chan 📂 Article 📅 2007 🏛 John Wiley and Sons 🌐 English ⚖ 104 KB 👁 1 views

## Abstract A series of sulfonamides (**2**–**4**) were prepared from natural amino acids and used as additives in the BINOL‐Ti(O__i__Pr)~4~ catalyzed enantioselective alkynylation of aldehydes. The reactions proceeded smoothly with good yields and very high ee's (up to 99%) in most cases. Chiralit