Trimethylstannane, substituted

The retrosynthesis involves the following transformations i) isomerisation of the endocyclic doble bond to the exo position ii) substitution of the terminal methylene group by a more stable carbonyl group (retro-Wittig reaction) iii) nucleophilic retro-Michael addition iv) reductive allylic rearrangement v) dealkylation of tertiary alcohol vi) homolytic cleavage and functionalisation vii) dehydroiodination viii) conversion of ethynyl ketone to carboxylic acid derivative ix) homolytic cleavage and functionalisation x) 3-bromo-debutylation xi) conversion of vinyl trimethylstannane to methyl 2-oxocyclopentanecarboxylate (67). 

Thermolytic decomposition of a substitution product, as a consequence of its slower formation, is observed in other cases also. Thus, reaction of (Mc3Sn)4N4 with trimethylstannane at 60°C, which leads primarily to an Mc3Sn/H exchange (/N—SnMc3 + Mc3SnH — —H + Mc3Sn—... 

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