Thietane and Selenetane Complexes by Thermal Cycloaddition of Vinyl Ethers to Transition-Metal-Coordinated Thio- And Selenoaldehydes - Crystal Structure of Pentacarbony(7-phenyl-2-oxa-8-thiabicyclo[4.2.0]octane-S)tungsten(0)

Article abstract of DOI:10.1002/cber.19961291005

Pentacarbonyl(thiobenzaldehyde)tungsten und pentacarbonyl(selenobenzaldehyde)tungsten (la and lb) undergo a thermal [2 + 2] cycloaddition with several vinyl ethers to give highly substituted transition metal-coordinated thietanes and selenetanes. The addition is highly regio- and stereospecific. The products undergo acid-catalyzed rearrangements, which lead to thermodynamically more stable diastereomers of the thietanes and selenetanes. The stereochemistry of both addition and rearrangement was established by reaction of deuterium-labeled vinyl ethers and by reaction of the cis and irons isomers of ethyl propenyl ether. The crystal structure of the bicyclic addition product of la and 3,4-dihydro-2H-pyran is reported. VCH Verlagsgeserischau mbK, 1996.