Regio- and Enantioselective Linear Cross-Dimerizations between Conjugated Dienes and Acrylates Catalyzed by New Ru(0) Complexes

New
naphthalene complexes of Ru(0) with various Ru­(η6-naphthalene)­(cyclic diene) (3) ligands catalyze
linear cross-dimerization between conjugated dienes and acrylates.
One of the noteworthy catalysts is the dibenzocyclooctatetraene complex 3d, which shows high catalytic activity for the cross-dimerization
between 1,3-pentadiene and methyl acrylate to give the cross-dimers
in 99% yield (branch/linear = 77/23) within 1 h at 50 °C with
1 mol % catalyst loading. When Ru­(η6-naphthalene)­[(−)-Ph-bod*]
(3f) was used as the catalyst, treatment of 2,4-dimethylhexa-2,4-diene
with tert-butyl acrylate produced the chiral cross-dimer
in 44% yield with 49% ee. This is the first example of enantioselective
cross-dimerization between conjugated dienes and substituted alkenes.