Bistannylated aromatic compounds

The photostimulated reaction of o-, m-, and p-C6H4Cl2 with Mc3Sn ions gives disubstitution in 58%, 90%, and 88% yield, respectively [39] in addition, methyl 2,5-dichlorobenzoate and methyl 3,6-dichloro-2-methoxybenzoate afford bistannylated aromatic compounds in 99% and 64% yields, respectively [40]. Disubstitution products are also obtained by the reaction of 2,6-and 3,5-dichloropyridine under photoinitiation in about 80% yield (Scheme 10.26). Even trisubstitution is possible by the photoinduced reaction of 1,3,5-C6H3C13 with Me3Sn ions in liquid ammonia, in 71% yield [39]. 

The synthesis of bistannylated aromatic compounds can be achieved in good yields via a simple two-step sequence from phenols [44]. This methodology enables, for example, the transformation of BINOL into the corresponding aryl diethylpho-sphate ester, which by reaction with Me3Sn ions in liquid ammonia under irradiation affords 2,2 -bis(trimethylstannyl)-l,l -binaphthyl in an overall yield of 66% (Scheme 10.27). 

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