Recyclable reagents biphenyl

The direct chlorination of iodoarenes 9 and 11 has been used for the preparation of 4,4 -bis(dichloroiodo)biphenyl (10) and 3-(dichloroiodo)benzoic acid (12) (Scheme 2.4), which are convenient recyclable hypervalent iodine reagents (Section 5.3) [66]. 

Reactions of (dichloroiodo)benzene with various monoterpenes in methanol proceed via the ionic mechanism and afford the respective products of chloromethoxylation of the double bond with high regio- and stereoselectivity [56]. Likewise, the reaction of a recyclable chlorinating reagent, 4,4 -bis(dichloroiodo)biphenyl... 

A simple method for the preparation of a-azido ketones and esters 500 in good yields by direct azidation of carbonyl derivatives 499 at the a-carbon using 4,4 -bis-(dichloroiodo)biphenyl and sodium azide has been reported (Scheme 3.198) [575]. The hypervalent iodine reagent, 4,4 -bis-(dichloroiodo)biphenyl, can be easily recycled from the reaction mixture. 

Various recyclable hypervalent iodine reagents based on the frameworks of 1,3,5,7-tetraphenyladamantane (65-67) [74], tetraphenylmethane (69-71) [75], biphenyl (73 and 74) [76] and terphenyl (76) [76] have been developed (Figure 5.3). Similarly to previously discussed reagent 56 (Scheme 5.23), aryl iodides 64,68,72... 

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