James W. Ringer -- PhD 1988

Scientific Career

Thesis Title
Preparation of Stannanes from Allyl Selenides. Synthesis and Mechanism.
Research Summary 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)

Current Position Dow Chemical

Carsten, Jim Ringer and Ken Yelm, June 1984

For comments, additions and corrections, send e-mail to Hans J. Reich