Hydrostannation unsaturated esters

The Stille adduct of 2-bromothiophene and l-ethoxy-2-tributyl-n-stannylethene or 1-ethoxy-l-tri-n-butylstannylethene is a masked thienyl aldehyde or a masked ketone, respectively [77-80]. Vinylstannane 93, derived exclusively as the -isomer from hydrostannation of bis(trimethyl-silyl)propargyl amine (92), was coupled with 2-bromothiophene to form ( )-cinnamyl amine 94 upon acidic hydrolysis [81, 82], In another case, stereoisomerically pure phenyl ( )-2-tributylstannyl-2-alkenoate 95, arising from Pd-mediated hydrostannation of phenyl ( )-2-alkynoate, was joined with 2-iodothiophene to deliver the stereodefmed trisubstituted a,p-unsaturated ester 96 [83, 84],... 

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