Unusual Regioselectivity in the Aldehyde Addition Reactions of Allenyl/Propargyl Zirconium Complexes Derived from gamma-(2-Pyridyl)propargyl Ethers: Synthesis of Multisubstituted alpha-Hydroxyallenes

Zirconium-mediated reactions of gamma-(2-pyridyl)-propargyl ethers with aldehydes afford alpha-hydroxyallenes selectively via the formation of allenyl/propargyl zirconium species. The reaction outcome is quite different to that of the reactions using prop