A Copper‐ and Phosphine‐Free Nickel(II)‐Catalyzed Method for C−H Bond Alkynylation of Benzothiazoles and Related Azoles. Issue 7 (7th June 2018)

• Record Type: Journal Article
• Authors: Patel, Ulhas N.; Punji, Benudhar
• Is Part Of: Asian journal of organic chemistry. Volume 7:Issue 7(2018)
• Page Start: 1390
• Page End: 1395
• Publication Date: 2018-06-07
• Subjects: azoles -- alkynylation -- C−H activation -- heterocycles -- nickel; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; 547.005
• DOI: 10.1002/ajoc.201800243
• Languages: English
• ISSNs: 2193-5807

Abstract

Abstract: A phosphine‐free nickel(II)‐catalyzed method for the C(2)−H bond alkynylation of (benzo)thiazoles, (benz)imidazoles, and oxazoles is described. Well‐defined and air‐stable (Phen)NiCl2 catalyst efficiently catalyzes the coupling of diverse azoles with alkynyl bromides without the use of a copper co‐catalyst, and the method tolerates synthetically important functional groups. Preliminary mechanistic studies on this Ni II ‐catalyzed alkynylation emphasize the homogeneous nature of the catalyst, and rule out a radical manifold for the reaction. The synthetic utility of this Ni‐catalyzed method is demonstrated by further functionalizing the alkynylated benzothiazoles to 3‐methyl‐2‐(alkynyl)benzo[ d ]thiazolium salts that are known DNA cleaving agents. Abstract : A nickel for a CuP : A phosphine‐free nickel(II)‐catalyzed method for the C(2)−H bond alkynylation of (benzo)thiazoles, (benz)imidazoles, and oxazoles, which proceeds smoothly without the use of a copper co‐catalyst, is described.