Benzyltrimethylammonium tetrachloroiodate

Lewis acid catalyst is normally required when ammonium polyhalides are used, although recourse does not have to be made to strong acids, such as aluminium trichloride. Bromination and iodination reactions are normally conducted in acetic acid in the presence of zinc chloride [32], but chlorination using the ammonium tetrachloroiodate in acetic acid does not require the additional presence of a Lewis acid [33]. Radical chlorination of toluenes by benzyltrimethylammonium tetrachloroiodate in the presence of AIBN gives mixtures of the mono-and dichloromethylbenzenes [34], Photo-catalysed side-chain chlorination is less successful [35], Radical bromination using the tribromide with AIBN or benzoyl peroxide has also been reported [36, 37],... 

Benzyltrimethylammonium tetrachloroiodate was less effective although nevertheless a stable chlorinating agent which with anisoie in acetic acid at 70°C during 24 hours afforded 4- and 2-chloroanisole (6 1) in 73% yield (ref. 108). 

Investigations led to the conclusion that A-chlorosuccinimide (NCS) in acetic acid is the reagent of choice for the selective monochlorination of various thiophenes [85]. Other chlorinating agents such as sulfuryl chloride, hypochlorous acid [86], benzyltrimethylammonium tetrachloroiodate [87] or tin(IV) chloride in the presence of lead(IV) acetate [88] were shown to be useful reagents for thiophene chlorination. 

Preparation by treatment of 3,5-diacetoxyac-etophenone with benzyltrimethylammonium tetrachloroiodate (BTMA ICl ) in acetic acid at 70° for 6 h (93%) [6098]. 

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