Octacarbonyldicobalt-Induced (1,3) H Shifts in 1-Methylallenecarboxylates and Allenic Lactones

Article abstract of DOI:10.1002/hlca.19870700419

The allenecarboxylates 1a,b and allenic lactones 4a,b undergo thermally induced (1,3) H shifts in the presence of Co2(CO)8.The non-isolated 1,3-dienes 2a,b react further affording the Diels-Alder adducts 3a,b in high yields.These adducts were not formed in the case of the 2-vinylbutenolides 5a,b.On irradiation in the presence of Co2(CO)8 or Mn2(CO)10, the studied allenes reacted in a different manner, yielding either cyclization products 7 and 8 or products 9 and 10, formed via H abstraction and solvent addition.