Palladium‐Catalyzed Arylation of a Sterically Demanding gem‐Dibromophosphaethene. Issue 16 (7th October 2016)

• Record Type: Journal Article
• Authors: Ito, Shigekazu; Shinozaki, Tomokazu; Mikami, Koichi
• Is Part Of: ChemistrySelect. Volume 1:Issue 16(2016)
• Page Start: 5260
• Page End: 5264
• Publication Date: 2016-10-07
• Subjects: Carbanions -- Cross-coupling -- Isomerization -- Palladium -- Phosphaalkenes; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201601105
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: The trans bromide of 2, 2‐dibromo‐1‐(2, 4, 6‐tri‐ t ‐butylphenyl)‐1‐phosphaethene (Mes*P=CBr2 ; Mes*=2, 4, 6‐ t Bu3 C6 H2 ) can be successfully substituted with an aryl group by using a palladium version of the Kumada‐Tamao‐Corriu cross‐coupling process. Predominant formation of the 2‐aryl‐2‐bromo‐1‐phosphaethene [( Z )‐Mes*P=C(Br)Ar] required suitable conditions including optimization of the ancillary phosphine ligand, thereby retarding the dual elimination of bromides leading to phosphaalkyne (Mes*C≡P). The 2‐aryl‐2‐bromo‐1‐phosphaethenes hold promise as versatile synthons for functional π‐conjugated molecules, and stereospecific transformations of the bromine atom by halogen‐metal exchange and palladium‐catalyzed arylations were demonstrated. Abstract : Stereoselective monoarylation of 2, 2‐dibromo‐1‐(2, 4, 6‐tri‐ t ‐butylphenyl)‐1‐phosphaethene (Mes*P=CBr2 ; Mes*=2, 4, 6‐ t Bu3 C6 H2 ) was achieved by using a palladium version of the Kumada‐Tamao‐Corriu cross‐coupling process including suitable ancillary phosphine ligands. Stereospecific transformations of the arylbromophosphethenes by halogen‐metal exchange and palladium‐catalyzed arylations are demonstrated.