Cycloisomerization of 1,6-Enynes Using Acetate as a Nucleophile under Palladium(II) Catalysis

An efficient method for the synthesis of five-membered
carbo- and heterocyclic compounds, including fused rings,
was reported using acetate as a nucleophile in the cyclization
of 1,6-enynes under palladium(II) catalysis. The reaction is
initiated by trans-acetoxypalladation of the alkynes and
quenched by either trans- or cis-deacetoxypalladation in the
presence of 2,2‘-bipyridine as the ligand. An example of the
catalytic asymmetric cyclization is presented with moderate
enantioselectivity using chiral bisoxazoline ligand.