Reference

Photochemistry of cyclododecanone

Photochemistry of cyclododecanone. Burchill, Peter J.; Kelso, A. Gordon; Power, Alan J. (Mater. Res. Lab., Dep. Def., Ascot Vale, Aust.). Aust. J. Chem., 29(11), 2477-84 (English) 1976. CODEN: AJCHAS. DOCUMENT TYPE: Journal CA Section: 74 (Radiation Chemistry, Photochemistry, and Photographic Processes) Quant. measurements of the photolytic reactions of cyclododecacanone gave quantum yields of reaction and of intersystem crossing as 0.56 and 0.88 resp., and a triplet lifetime of 1.7 .times. 10-7s. 830-13-7 and 61537-73-3 are just another two chemicals used in this study. Cyclobutanol formation accounts for most of the reaction with only a low yield of the Norrish II cleavage product; this contrasts markedly with the opposite behavior of acyclic ketones of similar size. The results may be explained by the apparent restriction of rotation in cyclododecanone mols. .

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

Palladium-Catalyzed Asymmetric Arylation, Vinylation, and Allenylation of tert-Cyclobutanols via Enantioselective C-C Bond Cleavage. Matsumura, Satoshi; Maeda, Yasunari; Nishimura, Takahiro; Uemura, Sakae (Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Kyoto 606-8501, Japan). Journal of the American Chemical Society, 125(29), 8862-8869 (English) 2003 American Chemical Society. CODEN: JACSAT. ISSN: 0002-7863. DOCUMENT TYPE: Journal CA Section: 21 (General Organic Chemistry) Section cross-reference(s): 75 A novel enantioselective C-C bond cleavage has been achieved using palladium catalysts and chiral N,P-bidentate ligands in the asym. arylation, vinylation, and allenylation of tert-cyclobutanols. In these reactions, the enantioselective b-carbon elimination of Pd(II) alcoholate formed in situ is the key step. Treatment of tert-cyclobutanols, e.g. I, with aryl bromides R1Br (R1 = Ph, 2-MeOC6H4, 4-ClC6H4, 1-naphthyl, 9-anthracenyl, etc.) in toluene in the presence of Pd(OAc)2, a chiral ferrocene-contg. N,P-bidentate ligand, and Cs2CO3 afforded optically active g-arylated ketones, e.g. R1CH2CHPhCH2COPh, in excellent yields with high enantioselectivity (up to 95% ee). When vinylating reagents R2CR3:CR4X [R2 = R3 = H, Me, R4 = H, X = Br; R2R4 = (CH2)4, R3 = H, X = F3CSO2O; etc.] were used instead of aryl bromides in reaction with I under the similar conditions, the asym. vinylation occurred to afford optically active g-vinylated ketones II in high yields with good to high enantioselectivity. When propargylic acetates R5CYCC(OAc)Me2 (R5 = Ph, MeO2C), which are known to generate (s-allenyl)palladium complexes with Pd(0) species, were used in reaction with I, asym. allenylation took place to afford optically active g-allenylated ketones III in moderate to good yields with moderate to high enantioselectivity.