发现在沸腾的三氟乙酸(TFA)中发生酰基戊二甲基苯与活化的芳烃(如苯甲醚)之间的容易的转酰基作用。通过产物分离和动力学阐明了乙酰戊五甲基苯(AcPMB)和苯甲醚与TFA的转酰化机理。该反应进行经由AcPMB的可逆protodeacetylation涉及的本位-protonated中间体B,得到五甲基苯和乙三氟乙酸酐,接着通过混合酸酐苯甲醚不可逆乙酰化。从而导致该机构本位-protonated中间体B由acetylmesitylene与[反应推导2H] TFA以及3,5-二氘代乙酰基乙酰间苯三甲与TFA的脱乙酰速率。这种中间体的形成还通过在稳定离子条件下在超酸溶液中对AcPMB的13 C nmr光谱研究独立地证实。
Sterically hindered acylarenes are deacylated to arenes in good yields on heating in boiling 1,2-dichloroethane containing a catalytic amount of triflic acid and water. Hindered arenecarboxylic acids undergo decarboxylation under the same conditions to give arenes in high yields.
Isolation, X-ray Structures, and Electronic Spectra of Reactive Intermediates in Friedel−Crafts Acylations
作者:M. G. Davlieva、S. V. Lindeman、I. S. Neretin、J. K. Kochi
DOI:10.1021/jo0501588
日期:2005.5.1
Reactive intermediates in the Friedel−Craftsacylation of aromatic donors are scrutinized upon their successful isolation and X-ray crystallography at very low temperatures. Detailed analyses of the X-ray parameters for the [1:1] complexes of different aliphatic and aromatic-acid chlorides with the Lewis acids antimony pentafluoride and pentachloride, gallium trichloride, titanium and zirconium tetrachlorides
Friedel–Crafts acylation, bromination, deuteration, and nitration of acetylpentamethylbenzene (APMB), 1-acetyl-2,3,4,6-tetramethylbenzene (ATMB), and 1-benzoyl-2,3,4,6-tetramethylbenzene (BTMB) and...
Preparation and Properties of Substituted Benzhydryl Carbonium Ions
作者:Hilton A. Smith、R. Gene Thompson
DOI:10.1021/ja01612a018
日期:1955.4
Regioselective side-chain nitration of polymethylbenzenes directed by an acyl function and its application to the synthesis of polysubstituted phthalic acid derivatives