Pd(O)-catalyzed addition of Me3SnSnMe3 to α,β-alkynic aldehydes and ketones. Synthesis of (Z)-β-trimethylstannyl α, β-alkenic aldehydes and ketones. Preparation and synthetic uses of substituted (Z)-4-trimethylstannyl-1,3-butadienes

Article abstract of DOI:10.1139/v96-234

Treatment (dry tetrahydrofuran, reflux) of the α,β-alkynic aldehydes 26-28 and ketones 29-36 with Me₃SnSnMe₃ in the presence of a catalytic amount of (Ph₃P)₄Pd provides fair to excellent yields of the corresponding (Z)-β-trimethylstannyl α,β-alkenic aldehydes 41-43 and ketones 44-51. The carbonyl compounds 41-51, upon reaction with methylenetriphenylphosphorane under suitable conditions, are smoothly converted into the (Z)-4-trimethylstannyl-1,3-butadienes 61-71, respectively. Treatment of the aldehyde 41 with the anion of trimethyl phosphonoacetate and the aldehyde 42 with the anion of the phosphonoacetate 73 produces excellent yields of the 5-trimethylstannyl-2,4-heptadienoates 72 and 74, respectively. The synthetic potential of (Z)-4-trimethylstannyl-1,3-butadienes is illustrated by the conversion of 62 into the functionalized, stereodefined conjugated dienes 76 and 78 and by transformation of 87 into the structurally novel diene 84. Diels-Alder reactions of 84 with tetracyanoethylene and dimethyl acetylenedicarboxylate provide the spiro[3.5]nonane derivatives 88 and 89, respectively.