Divinyl silyl ethers

Therefore, the aim of this work was to synthesize new silacyclic and oligomeric organosilicon compounds containing easily modifiable Si-O-R bonds, via competitive silylative coupling cyclization and polycondensation of divinyl-substituted silyl ethers in the presence of ruthenium hydride complex. 

The synthetic problem is now reduced to cyclopentanone 16. This substance possesses two stereocenters, one of which is quaternary, and its constitution permits a productive retrosynthetic maneuver. Retrosynthetic disassembly of 16 by cleavage of the indicated bond furnishes compounds 17 and 18 as potential precursors. In the synthetic direction, a diastereoselective alkylation of the thermodynamic (more substituted) enolate derived from 18 with alkyl iodide 17 could afford intermediate 16. While trimethylsilyl enol ether 18 could arise through silylation of the enolate oxygen produced by a Michael addition of a divinyl cuprate reagent to 2-methylcyclopentenone (19), iodide 17 can be traced to the simple and readily available building blocks 7 and 20. The application of this basic plan to a synthesis of racemic estrone [( >1] is described below. 

A similar coupling with a,p-unsaturated acid chlorides provides p-silyl divinyl ketones (Nazarov reagents). These ketones cyclize in the presence of a Lewis acid, particularly BF3 etherate, to cyclopentenones, generally with retention of the silyl group. 

Oxybis(Av V-dimethylacetamidetriphenylstibonium) perchlorate, 3905 [l,l -Oxybis[ethane]]tris(trimethyl silyl)aluminium, see Tris(trimethylsilyl)aluminium etherate, 3614 f l,l -Oxybisethene, see Divinyl ether, 1516 2,2 -Oxybis(ethyl nitrate), 1594 f Oxybismethane, see Dimethyl ether, 0915... 

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