Palladium-Catalyzed Asymmetric Arylation, Vinylation, and Allenylation of tert-Cyclobutanols via Enantioselective C−C Bond Cleavage

• Published in: Journal of the American Chemical Society Vol. 125; no. 29; pp. 8862 - 8869
• Main Authors: Matsumura, Satoshi, Maeda, Yasunari, Nishimura, Takahiro, Uemura, Sakae
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 23.07.2003
• Subjects: Chemical reactivity; Chemistry; Exact sciences and technology; Organic chemistry; Reactivity and mechanisms; Arylation; Catalytic reaction; Enantioselectivity; Tertiary phosphine; Palladium Complexes; Catalyst selectivity; Organic ligand; Transition metal Complexes; Complex catalyst; Experimental study; Vinylation; Asymmetric reaction; Platinoid Complexes; Catalyst activity
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja035293l

A novel enantioselective C−C bond cleavage has been achieved using palladium catalysts and chiral N,P-bidentate ligands in the asymmetric arylation, vinylation, and allenylation of tert-cyclobutanols. In these reactions, the enantioselective β-carbon elimination of Pd(II) alcoholate formed in situ is the key step. Treatment of tert-cyclobutanols with arylating reagents in toluene in the presence of Pd(OAc)2, a chiral ferrocene-containing N,P-bidentate ligand, and Cs2CO3 affords optically active γ-arylated ketones in excellent yields with high enantioselectivity (up to 95% ee). When vinylating reagents are used in place of arylating ones, the asymmetric vinylation also proceeds to afford optically active γ-vinylated ketones in high yields with good to high enantioselectivity. When propargylic acetates are used, which are known to generate (σ-allenyl)palladium complexes with Pd(0) species, asymmetric allenylation occurs to afford optically active γ-allenylated ketones in moderate to good yields with moderate to high enantioselectivity.