[66222-29-5] · C13H29ISn · Tri-n-butyl(iodomethyl)stannane · (MW 431.03)
Alternate Name: tributyl(iodomethyl)tin.
Physical Data: colorless liquid; bp 100-110 °C/0.01 mmHg.
Handling, Storage, and Precautions: potentially toxic; should be handled in a well ventilated hood.
Tri-n-butyl(iodomethyl)tin (1) has been used extensively as an electrophile in the preparation of a-heteroalkylstannanes such as tri-n-butylstannylmethyl ethers,2 N-acylated a-aminostannanes,1 and S-stannylmethyl phosphinothioates.6 Tri-n-butylstannylmethyl ethers of allylic alcohols undergo tin-lithium exchange and [2,3]-sigmatropic rearrangement upon treatment with n-Butyllithium. For example, the stannylated ether (2) provides the homoallylic alcohol (3) with nearly exclusively the (Z) configuration (eq 1).2
Diastereoselective [2,3]-Wittig rearrangements of this type have been reported.7 This reaction sequence has been applied to the synthesis of alkene dipeptide isosteres,8 as well as a number of natural products including (-)-punctatin A (eq 2).9 The homoallylic (tri-n-butylstannyl)methyl ether (4) undergoes stereoselective anionic cyclization to the cis-2,4-disubstituted tetrahydrofuran (5) upon transmetalation with n-BuLi (eq 3).10 Tin-lithium exchange of the oxazolidinone-derived a-aminostannane (6) generates nitrogen-substituted organolithium compounds which react with a variety of electrophiles (eq 4).1
Tri-n-butyl(iodomethyl)tin is a useful reagent for the preparation of alkenes from sulfides,11 sulfones,12 and nitriles.13 The moderately hindered sulfone (7) is converted to the corresponding exocyclic alkene by fluoride-induced desulfonylstannylation of (8) (eq 5).14 Tri-n-butyl(iodomethyl)tin has also been used to prepare (tri-n-butylstannyl)methyllithium (9), which reacts with electrophiles as a methylene double anion equivalent.15 For example, transmetalation of (1) using n-BuLi followed by addition of an ester generates the corresponding ketone enolate which may participate in aldol reactions (eq 6).
Steven K. Davidsen
Abbott Laboratories, Abbott Park, IL, USA