[208164-59-4] · C16H33ISn · (MW 471.03)
(bifunctional reagent for cyclohexenone annulations2)
Alternate Names: [(Z)-4-iodobut-1-enyl]tributylstannane.
Physical Data: colorless liquid.
Solubility: soluble in THF, diethyl ether, CHCl3.
Preparative Methods: sequential treatment of acetylene with Bu3SnCu(Bu)(CN)Li2 and ethylene oxide provides (Z)-4-tributylstannylbut-3-en-1-ol (1)3 which, upon treatment with Ph3P·I2, affords the title reagent (2) (
Handling, Storage, and Precautions: organostannane compounds are toxic and must be prepared, purified, and used in a fume hood.4
Treatment of dimethylhydrazone (3) with LDA, followed by addition of a mixture of the title reagent (2) and HMPA, gives the alkylated hydrazone (4). Stereospecific iododestannylation5 and hydrolysis of the hydrazone provides vinyl iodide (5), which readily undergoes ring closure upon treatment with n-butyllithium. Oxidation of the resultant tertiary allylic alcohol (6) with PCC on alumina affords the corresponding cyclohexenone (7).
Annulation of substrates containing ketal groups (
Cycloheptenones are obtained by application of the above protocol using (Z)-5-iodo-1-(tributylstannyl)pent-1-ene (8) (
University of British Columbia Vancouver, British Columbia, Canada