Expeditious Access to Spiro-Fused 2,5-Cyclohexadienones <i>via</i> Thio(seleno)cyanative <i>ipso</i>-Cyclization
作者:Chada Raji Reddy、Uprety Ajaykumar、Dattahari H. Kolgave
DOI:10.1021/acs.joc.0c02270
日期:2020.12.4
A facile oxidative dearomatization of N-(p-methoxyaryl)propiolamides has been established for the synthesis of spiro-fused 2,5-cyclohexadienone frameworks via thio(seleno)cyanative ipso-cyclization in the presence of cericammoniumnitrate (CAN) as the oxidant. The present method, involving the formation of C–S and C–C bonds, was also extended to (p-methoxyaryl)propiolates for thiocyanative ipso-cyclization
A Lewis acid-catalyzed cyclization of N-(p-methoxyphenyl)-3-phenylpropionamide with N-thiocyanosuccinimide has been accomplished under mild conditions. Thus, a series of thiocyanato-containing spirocyclohexadienones was obtained in moderate to excellent yields with a good functional group tolerance and a wide range of substrates. It provides an alternative approach for the synthesis of functionalized
Electrophilic <i>ipso</i>-Cyclization of <i>N</i>-(<i>p</i>-Methoxyaryl)propiolamides Involving an Electrophile-Exchange Process
作者:Bo-Xiao Tang、Qin Yin、Ri-Yuan Tang、Jin-Heng Li
DOI:10.1021/jo8018297
日期:2008.11.21
A novel electrophilic ipso-cyclization involving an electrophile-exchange process has been developed. In the presence of CuX (X = I, Br, SCN) and electrophilic fluoride reagents, a variety of N-(p-methoxyaryl)propiolamides and 4-methoxyphenyl 3-phenylpropiolate were cyclized to selectively afford the corresponding spiro[4.5]decenones in moderate to good yields. It is noteworthy that two azaquaternary tricyclic products were synthesized through a two-step pathway involving an electrophilic ipso-cyclization and then an intramolecular Heck reaction.