Journal of the American Chemical Society p. 5937 - 5942 (1991)
Update date:2022-08-03
Topics:
Attina', Marina
Cacace, Fulvio
Ricci, Andreina
The reactivity of (trimethylsilyl)benzene (TSB) and (trimethylsilyl)toluenes (TST) toward i-C3H7+ and (CH3)2F+ has been studied in the gas phase in the interval from 0.6 to 3040 Torr and from 37.5 to 100 °C by mass spectrometric and radiolytic techniques. The systematic investigation of the dependence of the relative rate of the alkylation and alkyldesilylation processes promoted by i-C3H7+ on the nature and the concentration of gaseous bases has allowed an evaluation of the rate constant of the isomerization via proton 1,2-shifts of the alkylated adducts from TSB into the corresponding ions protonated ipso to the SiMe3 group. The results, i.e., ki = 1.6 X 109 s-1 at 310 K and Ei? ≈ 9.5 kcal mol-1, represent the first experimental evaluation of the kinetic parameters of proton 1,2-shifts within gaseous arenium ions, generally too fast to be monitored by mass spectrometric techniques, and are in excellent agreement with theoretical and solution-chemistry studies of the model C6H7+ ion. The selectivity of the alkylation of TSB and of m- and p-TST is discussed, particularly as regards direct ipso substitution and the steric hindrance to deprotonation of the ortho-isopropylated adducts.
View MoreShandong Wanda Organosilicon New Material Co., Ltd
Contact:+86-21-54177116;54302881
Address:R1318 Greenland No. 3 Lane 58 Xinjian East Rd., Minhang
xi'an taima biological engineering co., ltd.
Contact:+8615619038117
Address:6 No,keji road xi'an city of china
Hangzhou Showland Technology Co., Ltd.
Contact:86-571-88920516
Address:ROOM2118,NO.553,WENSAN ROAD,HANGZHOU,CHINA
Yangling Ciyuan biotech Co., Ltd.
Contact:86-15802970736
Address:2-1804, International Park Mansion, No.2, South Fengdeng Road, Lianhu District
Xi'an Unique Electronic and Chemical Co., Ltd.
Contact:+86-029-88238008
Address:1703# B BUILDING WEST ELECTRONIC ZONE, XI'AN, CHINA
Doi:10.1080/00945719809351902
(1998)Doi:10.1021/jm030025j
(2003)Doi:10.1021/jacs.6b10462
(2016)Doi:10.1021/ja000806z
(2000)Doi:10.1021/jo971521g
(1998)Doi:10.1021/om971000j
(1998)