P. De March et al., Highly efficient, enantioselective synthesis of (+)-grandisol from a C-2-symmetric bis(alpha,beta-butenolide), ORG LETT, 2(2), 2000, pp. 163-165
[GRAPHICS]
A new, very efficient, enantioselective synthesis of the sexual attracting
insect pheromone (+)-grandisol has been developed, in which the key step is
the double [2 + 2] photocycloaddition of ethylene to a bis(alpha,beta-bute
nolide) readily available from D-mannitol. The C-2 symmetry of the substrat
e and the appropriate protection of the central diol unit are the crucial f
eatures for the high diastereofacial discrimination during the cycloadditio
n process.