Jim developes a synthesis of organotin compounds based on the reaction of organoselenium compounds with trimethylstannyllithium. He found that a variety of activated selenides (propargyl, allyl and benzyl selenides, selenoketals) reacted smoothly with Me3SnLi to formally replace the C-Se bond with C-Sn. This allowed use of the chemistry of metalated selenides to prepare stannanes.
1,1-Bis-stannyl derivatives can be prepared by a novel "counterattacking" reaction:
Since selenides are not normally good substrates for SN2 substitutions, the mechanism here must be more complicated, and Jim performed a number of experiments to probe for intermediates in these substitutions. It seems likely that the reaction involves first a Li/Se exchange (perhaps through an electron-transfer process), followed by reaction of the Me3SnSePh with the allylic, propargylic or benzylic lithium reagent.
|Papers||"Organoselenium Chemistry. Preparation of Allylic, Allenic and Propargylic Stannanes by Substitution of Phenylseleno with Trimethylstannyl," H. J. Reich and J. W. Ringer, J. Org. Chem. 1988, 53, 455. (Communication)|