Dehydrodimerization of iodobenzenes to iodinated biaryls

Abstract

The molybdenum pentachloride-mediated oxidative coupling of iodo-substituted electron rich benzenes without the loss of the iodo-substituents is reported. The presented methodology is an environmentally friendly alternative to known thallium(III)- and lead(IV)-reagents. Even 2,2',6,6'-tetraiodobiphenyl derivatives are easily accessible.

Oxidative Coupling Reactions Mediated by MoCl5 Leading to 2,2′‐Cyclolignans: The Specific Role of HCl

“…[13Ϫ15] Based on the Lewis acid catalyzed reactions, MoCl 5 is considered as active as TiCl 4 . [16] Initially, we anticipated that a strong Lewis acid would activate the remaining molybdenum chloride clusters and, therefore, mediate the oxidative coupling reactions.…”

Oxidative Coupling of Diaryldisulfides by MoCl5 to Thianthrenes

“…[16][17][18] MoCl 5 represents a one-electron oxidant, [19] which is compatible with a variety of functional groups. [20,21] A detailed comparative study of King et al supports the potential of MoCl 5 as useful reagent in Scholl-type reactions. [22] The performance is similar to that of phenyliodineA C H T U N G T R E N N U N G (III)-bistrifluoroacetate (PIFA).…”

Iodinated Biaryls Synthesized by the Direct Dehydrodimerization of Iodoarenes Using Phenyliodine(III) Bis(trifluoroacetate) (PIFA)

“…The synthetic potential of the PIFA/BF 3 ¥ Et 2 O mixture is apparent in the conversion of 9 which provides remarkably better results than the MoCl 5 -mediated process (entry 8). [7] By applying slightly milder reaction conditions, substrates with benzodioxole moieties are successfully subjected to the dehydrodimerization process (entries 5 and 6).…”

“…[6] Recently, we reported an environmentally friendly alternative by using MoCl 5 for the oxidative dimerization of iodoveratrole derivatives. [7] Application of this methodology to substrate 9 even allows a direct synthesis of a 2,2',6,6'-tetraiodobiphenyl. To improve the solubility of the multiply iodinated biaryls for further purposes, the introduction of solubilizing groups in the alkoxy side chains is of great interest.…”