Ethylene three carbon atom products from

There is a dramatic kinetic stabilization by bulky substituents of the three-membered ring products from silylene addition to jr-bonds. Addition of t-Bu2Si to ethylene led to the first silirane with no substituents on its ring carbon atoms as a distillable liquid 164. Interestingly, l,l-di(terf-butyl)silirane does not undergo photochemical or thermal silylene extrusion, but instead polymerizes. A distillable silirane was also reported from addition of t-Bu2Si to 2-methylstyrene165. 

The three additional carbon atoms at Cio in plomestane (11-6) technically remove that agent from the gonane series. The chemistry for its preparation is, however, more closely related to that of 19-nor compounds, hence its listing among gonanes. The synthesis that leads to that compound starts by careful oxidation of the hydroxyl group at C17 in the Birch reduction product 1-3 to afford the 3,17-diketone 11-1 (Scheme 4.11). Reaction of that intermediate with ethylene... 

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