Facile Aromatic Nucleophilic Substitutions Observed for the Triarylcarbenium Ions, [(4-YC<sub>6</sub>H<sub>4</sub>)<i>Φ</i><sub>2</sub>C]<sup>+</sup>[<i>Φ</i>= 2,6-(MeO)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>; Y = MeO, Cl, Me<sub>2</sub>N, HO]
作者:Masanori Wada、Tetsuya Watanabe、Satoko Natsume、Hisashi Mishima、Katsuhiko Kirishima、Tatsuo Erabi
DOI:10.1246/bcsj.68.3233
日期:1995.11
Triarylmethanols of type (4-YC6H4)Φ2COH Φ = 2,6-(MeO)2C6H3; Y = MeO, Cl, Me2N} were prepared. The methanol, (4-MeOC6H4)Φ2COH, reacted with acids in a variety of solvents to give the triarylcarbenium salts, [(4-MeOC6H4)Φ2C]X or [(4-HOC6H4)Φ2C]X, or 4-bis(2,6-dimethoxyphenyl)methylene-2,5-cyclohexadienone, O=C6H4=CΦ2, depending on the conditions. These carbenium salts further reacted in alcohols, ROH, to give the triarylmethanes, (4-ROC6H4)Φ2CH (R = Me, Et), where the para-substituent, MeO or HO, was substituted by the solvent, accompanied by a reduction at the central carbon. The methanol, (4-ClC6H4)Φ2COH, also reacted with acid to give the carbenium salt or the triarylmethane, depending on the conditions. While the methanol, (4-Me2NC6H4)Φ2COH, also gave the carbenium salt, [(4-Me2NC6H4)Φ2C]X, it was inert against the formation of the triarylmethane under analogous conditions. It reacted with aqueous sodium hydroxide to give O=C6H4=CΦ2 rather than the original methanol. The para-substituent of [(4-MeOC6H4)Φ2C]X was substituted by di- and monoalkylamines, RR′NH, to give [(4-RR′ NC6H4)Φ2C]X (R,R′ = Me,Me; Et,Et; Me,H; Et,H; Bu,H). While [(4-ClC6H4)Φ2C]X reacted with the dialkylamines to give [(4-RR′NC6H4)Φ2C]X, it reacted with monoalkylamines, RNH2, to give [(4-ClC6H4)Φ2C–NRH2]X. [(4-Me2NC6H4)Φ2C]X was hydrolyzed in the presence of diethylamine to give O=C6H4=CΦ2, but reacted with monoalkylamines to give RN=C6H4=CΦ2.
制备了三芳基甲醇类(4-YC_6H_4)Φ_2COHΦ=2,6-(MeO)_2C_6H_3; Y=MeO,Cl,Me_2N}化合物。甲醇(4-MeOC_6H_4)Φ_2COH与酸在不同的溶剂中反应,在不同的条件下可以生成三芳基碳镭盐[(4-MeOC_6H_4)Φ_2C]X或[(4-HOC_6H_4)Φ_2C]X或者4-双(2,6-二甲氧苯基)亚甲基-2,5-环己二烯酮O=C_6H_4=CΦ_2。这些碳镭盐进一步在醇ROH中反应,生成三芳基甲烷(4-ROC_6H_4)Φ_2CH(R=Me,Et),其中的对位取代基MeO或HO被溶剂所取代,同时中心碳原子被还原。甲醇(4-ClC_6H_4)Φ_2COH在酸的作用下,条件不同时可以生成碳镭盐或三芳基甲烷。而甲醇(4-Me_2NC_6H_4)Φ_2COH虽然也生成了碳镭盐[(4-Me_2NC_6H_4)Φ_2C]X,但在相似的条件下并不发生生成三芳基甲烷的反应。它在氢氧化钠水溶液作用下生成O=C_6H_4=CΦ_2而不是原来的甲醇。碳镭盐[(4-MeOC_6H_4)Φ_2C]X的对位取代基被二烷基胺和单烷基胺RR'NH取代,生成[(4-RR'NC_6H_4)Φ_2C X(R,R'=Me,Me;Et,Et;Me,H;Et,H;Bu,H)。碳镭盐[(4-ClC_6H_4)Φ_2C]X在二胺作用下生成[(4-RR'NC_6H_4)Φ_2C]X,而在单烷基胺作用下生成[(4-ClC_6H_4)Φ_2C-NRH_2]X。碳镭盐[(4-Me_2NC_6H_4)Φ_2C]X在二乙胺作用下水解生成O=C_6H_4=CΦ_2,而在单烷基胺作用下生成RN=C_6H_4=CΦ_2。