A Strategy for the Triarylation of Pyrrolo­pyrimidines by Using Microwave‐Promoted Cross‐Coupling Reactions

Abstract

A new pyrrolo [2,3-d]pyrimidines bearing three aryl groups at 2-, 4-and 6-positions were prepared by arylation of 7-methyl-2-methylthio-4-chloro-6-phenylpyrrolo [2,3-d]pyrimidine (6) with the corresponding arylboronic acid under Suzuki-Miyaura conditions, followed by a second arylation using a Liebeskind-Srogl cross-coupling reaction. A parallel study beginning by the C-2 chemoselective arylation of 6 under Liebeskind-Srogl conditions followed by Suzuki-Miyaura coupling at C-4 was carried out and the results compared. All the tranformations have been realized under microwave irradiation.

The Liebeskind–Srogl Cross‐Coupling Reaction and its Synthetic Applications

“…Thereafter, the same strategy was utilized by Guillaumet and co‐workers in the preparation of 2,4,6‐triarylatedpyrrolo[2,3‐ d ]pyrimidines ( 60 ; Scheme ) . Commencing with key intermediate 58 , two feasible sequences were explored and route a was found to be a better choice in terms of the overall yield and ease of purification.…”

Efficient room temperature catalytic synthesis of alternating conjugated copolymers via C-S bond activation

“…Furthermore, C-S bonds are well tolerated functional groups in most other catalytic cross-coupling reactions, such as Suzuki, Stille, etc. 20 , 21 , and importantly, the potentially competing homocoupling of C-S bonds has never been reported, implying that inert C-S bonds will avoid or minimize homocoupling by-products 22 – 24 . Finally, C-S bond activation using unique additives may substantially lower the activation energies of the desired coupling/polymerization reactions 22 , 24 , thereby allowing polymerization reactions to proceed near room temperature.…”

Microwave-Assisted Palladium-Catalyzed Cross-Coupling Reactions: Generation of Carbon–Carbon Bond

“…The later was performed between 4-aryl-2-(methylthio)pyrrolo[3,2-d]pyrimidines and boronic acids using Pd(PPh 3 ) 4 and copper(I) 3-methylsalicylate (CuMeSal) in THF at 100 • C for 1 h (Scheme 56). The desulfurative reaction proceeded smoothly in the presence of either electron-donating, electron-withdrawing, or heterocyclic substituents on the arylboronic acids, leading to the products in high yields [122]. scope of the protocol was further extended to solid-phase-linked pyrazinones, oxazinones, pyrazines, and phenyl thioesters [119].…”