Infrared spectroscopic investigations on the metallation of terminal alkynes by Zn(OTf) ₂

Abstract

An IR study of terminal acetylenes and Zn(OTf)2 in the presence of amine bases provides evidence that is consistent with the generation of Zn-acetylides.

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

“…1), and Et 3 N to afford the desired products in high yields and enantioselectivities in the addition of terminal alkynes to aldehydes. 1,2,15,16 In this approach, the zinc alkynylides are generated in situ from terminal alkynes and Zn(OTf) 2 in the presence of amine base. [15][16][17][18][19][20] Another system involves the use of Et 2 Zn or Me 2 Zn to prepare in situ the alkynylzincs.…”

Stereoselective Conjugate Addition Reactions Using In Situ Metallated Terminal Alkynes and the Development of Novel Chiral P,N-Ligands

“…14 In 1999, our group reported a distinct method for the formation of zinc alkynylides under very mild and operationally simple conditions using Zn(OTf) 2 and an amine base at room temperature. 15,16 The alkynylides obtained under these conditions react in situ with a variety of electrophiles such as nitrones, aldehydes, ketones, and N-acylimminium ions. 4, 17 The addition of such alkynylides to aldehydes can be performed in an asymmetric fashion in the presence of inexpensive N-methylephedrine.…”

Zinc(II)‐Catalyzed Synthesis of Propargylamines by Coupling Aldimines and Ketimines with Alkynes

“…Among the various metal acetylides, Cu and Zn acetylides are more nucleophilic. [22] Zinc acetylides have been shown to be even more reactive then their Cu counterparts when treated with nitrones, according to previous investigations by Carreira. [23] Zinc triflate has also been used in some special cases such as the addition of cyclopropylacetylene to reactive cyclic trifluoromethylated N-acylimines.…”