Pd-catalyzed intramolecular addition of active methylene compounds to alkynes with subsequent cross-coupling with (hetero)aryl halides. Issue 68 (3rd December 2019)

• Record Type: Journal Article
• Authors: Błocka, Aleksandra; Woźnicki, Paweł; Stankevič, Marek; Chaładaj, Wojciech
• Is Part Of: RSC advances. Volume 9:Issue 68(2019)
• Page Start: 40152
• Page End: 40167
• Publication Date: 2019-12-03
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9ra08002c
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A tandem cyclization/coupling of acetylenic active methylene compounds with aryl halides features broad scope and excellent functional group compatibility. Mechanistic studies identified 5- exo-dig cyclization as the rate limiting step. Abstract : We report an efficient protocol for tandem Pd-catalyzed intramolecular addition of active methylene compounds to alkynes, followed by subsequent cross-coupling with (hetero)aryl bromides and chlorides. The reaction proceeds under mild conditions, providing excellent functional group tolerance, including unprotected OH, NH2 groups, enolizable ketones, or a variety of heterocycles. Mechanistic studies point towards a catalytic cycle involving oxidative addition, intramolecular nucleophilic addition to the Pd(ii )-activated alkyne, and reductive elimination, with 5- exo-dig cyclization being the rate limiting step.