Evidence for the Formation of the (Ph₃P)₂Pt Complex of 3,7-Dimethyltricyclo[3.3.0.0^3,7]oct-1(5)-ene, the Most Highly Pyramidalized Alkene in a Homologous Series. Isolation and X-ray Structure of the Product of the Ethanol Addition to the Complex

Attempts to isolate the (Ph₃P)₂Pt complex of the highly pyramidalized olefin 3,7-dimethyltricyclo[3.3.0.0^3,7]oct-1(5)-ene 2 by generation of 2 in the presence of (Ph₃P)₂PtC₂H₄, followed by crystallization of the complex (2-Pt) from THF−ethanol, resulted in the isolation of the adduct of 2-Pt with ethanol (5). Calculations confirm that addition of alcohol across the C1−C5 bond is more favorable in 2-Pt than in the corresponding (Ph₃P)₂Pt complexes of less pyramidalized olefins, despite the stronger Pt−C bonds in 2-Pt.