Synthesis of vinylic tellurides and synthetic applications

Abstract

To a solution of alkenyl zirconocene, which was conveniently generated in situ by the hydrozirconation of alkyne, was added phenyltellurenyl iodide. After hydrolysis, E-vinylic tellurides were isolated. Hydrozirconation of acetylenic tellurides afforded the first examples of 1, 1-bimetalloalkenes of tellurium and zirconium. Z-vinylic tellurides were obtained after hydrolysis of these intermediates. These 1,1-bimetalloakenes reacted with acyl halides to obtain (Z)-α-organotelluro-α,β-unsaturated carbonyl compounds via Zr-Cu transmetalation. Ketene organyltelluroacetals were obtained stereoselectively by the hydrozirconation of acetylenic tellurides and then transmetalation using organyltellurenyl iodides. Transmetalation of ketene telluroacetals was performed by using n-BuLi. 1,1-Bimetalloalkenes of Sn/Te and Sn/Se were obtained stereoselectively by the hydrozirconation of acetylenic stannanes and then transmetalation using organyltellurenyl iodides or phenylselenenyl bromide. Transmetalation of 1,1-Bimetalloalkenes of Sn/Te and Sn/Se was performed by using n-BuLi. Trans metalation of 1-trialkylstannylvinylic selenides shows very high yields and stereospecificity with electrophiles. Reaction of zirconacyclopentadienes with phenyltellurenyl iodide gave tellurophene via unusual rearrangement of zirconium complex. 1-Substituted (1E, 3E)-1,3-butadienyl phenyl tellurides and internal vinylic tellurides were synthesized stereoselectively using the preferential migration of the alkenyl or alkyl group from boron to the adjacent alkynyl carbon atom.