Catalysis of Diene Polymerization and Diels-Alder Reactions by an Octahedral Tungsten Nitrosyl Lewis Acid. X-ray Crystal Structure of the η1-Acrolein Complex (cis-Me3P)(trans-NO)(CO)3W-O=C(H)C(H)=CH2

Article abstract of DOI:10.1021/jo00232a049

Cyclopentadiene and isoprene are polymerized by 0.1 mol percent (Me3P)(CO)3(NO)W-FSbF5 (1), and catalysis of the Diels-Alder reactions of cyclopentadiene or butadiene with α,β-unsaturated enones is also induced by as little as 0.1 mol percent 1; the X-ray structure of the adduct of 1 and acrolein, the presumed catalytic intermediate, reveals a simple Lewis acid interaction of the tungsten with the acrolein oxygen.