Platinum-Catalyzed Selective Tin-Carbon Bond Formation

Abstract

In conclusion, two improved methods for the selective synthesis of monoorganotin trihalides were developed. The platinum-catalyzed Kocheshkov redistribution reaction of dialkyltin dichlorides with tin tetrachloride is the most interesting. Contrary to the other two methods described (the direct reaction of organic halides with tin(II) halides and the use of (NCN)Sn(IV)-butyl complexes as alkylating agents), this novel method works for a range of monoalkyltin trichlorides, affording high yields (up to 94%) and high selectivities (up to 96%). Moreover, the platinum catalysts used are either commercially available or easy to prepare. Since the reaction of R2SnCl2 (R = alkyl) with SnCl4 is not problematic anymore, direct conversion of R4Sn into four equivalents of RSnCl3 was also possible (for R = n-Bu, 83% isolated yield). This is a great improvement of the currently used method in which R4Sn reacts with two equivalents of SnCl4 to afford RSnCl3 in 66% yield with 33% of R2SnCl2 as side-product. Although further process optimization will be necessary, we conclude that the method has potential for industrial application, especially in the case that dialkyltin dichloride as by-product is undesirable.