69048-76-6Relevant academic research and scientific papers
Cobalt-catalyzed regioselective carbocyclization reaction of o-iodophenyl ketones and aldehydes with alkynes, acrylates, and acrylonitrile: A facile route to indenols and indenes
Chang, Kuo-Jui,Rayabarapu, Dinesh Kumar,Cheng, Chien-Hong
, p. 4781 - 4787 (2007/10/03)
An efficient cobalt-catalyzed carbocylization for the synthesis of indenols and indenes and a new method for reductive decyanation are described. 2-Iodophenyl ketones and aldehydes 1a-g undergo carbocyclization with various disubstituted alkynes 2a-k in the presence of Co(dppe)I2 and zinc powder in acetonitrile at 80 °C for 3 h to afford the corresponding indenol derivatives 3a-s and 4a-m in good to excellent yields. For some unsymmetrical alkynes, the carbocyclization was remarkably regioselective, affording a single regioisomer. The cobalt-catalyzed carbocyclization reaction was successfully extended to the synthesis of indene derivatives. Thus, the reaction of 2-iodophenyl ketones and aldehydes (1) with acrylates H2C=CHCO 2R (7a-d) and acrylonitrile H2C= CHCN (7e) proceeds smoothly in the presence of Co(dppe)Cl2/dppe and zinc powder in acetonitrile at 80 °C for 24 h to afford the corresponding indenes 8a-k and 9a-c in moderate to good yields. Interestingly, when 7e was employed for the carbocylization, reductive decyanation also occurred to give an indene derivative without the cyano functionality. A possible mechanism for this cobalt-catalyzed carbocyclization reaction is also proposed.
Cleavage of Methylenedioxy Ring. II. Cleavage with Sodium Phenoxide and Methoxide in Dimethyl Sulfoxide
Kobayashi, Shigeru,Imakura, Yasuhiro,Horikawa, Ritsuko
, p. 1287 - 1293 (2007/10/02)
Regioselective cleavage of the methylenedioxy ring in piperonals (1, 6, and 7) and 3,4-methylenedioxynitrobenzenes (8 and 9) by oxide ions in dimethyl sulfoxide was achieved: the 4-hydroxybenzene derivatives (2, 10-13, and 22) were obtained with the phenoxide ion, while the 3-hydroxybenzene derivatives (4, 18-21, 23, 26, and 29) were obtained with the methoxide or benzyloxide ion.Keywords - cleavage of methylenedioxy ring; regioselectivity; piperonals; 3,4-methylenedioxynitrobenzenes; sodium phenoxide; sodium methoxide; dimethyl sulfoxide; 3-hydroxybenzene derivatives; 4-hydroxybenzene derivatives; NMR spectra
