We have previously described the synthesis of dienes or enynes bearing a carboxylic function from β-iodovinylic acids and vinyltin or alkynylzinc reagents. 12., , and We have also reported the stereoselective one-pot synthesis of α-pyrones under palladium complex catalysis by coupling tributylstannylallenes with (Z)-iodovinylic acids. 13 Our aim here was to prepare allenylsubstituted alkenoic amides which we believed would exclusively undergo 6-endo mode cyclisation ...
