Synthesis and x-ray crystallographic analysis of pentacoordinate 1,2-oxasiletanides, intermediates of the Peterson reaction

Donor-Stabilized Silacyclobutanone: A Precursor of 1-Silaketene via Retro-[2 + 2]-Cycloaddition Reaction at Room Temperature

“…Thermally unstable four-membered metallacycles, which easily fragment into two unsaturated fragments via a formal retro-[2 + 2]-cycloaddition reaction, are well-known as the key intermediates of the olefin metathesis reaction . In silicon chemistry, the thermally unstable cyclic anionic pentacoordinate oxasiletanes V are the intermediates of the Peterson olefination reaction . In marked contrast, the more closely related silacyclobutanes VI , silicon/carbon-based four-membered metallacycles, are thermally stable, and the retro-[2 + 2]-cycloaddition reaction requires significant thermal activation (400–460 °C). , Here we report the synthesis and isolation of the first example of a donor-stabilized silacyclobutanone 2 (type IV ) which, under mild conditions (room temperature) undergoes a [2 + 2]-cycloreversion to generate a transient 1-silaketene derivative.…”

Peterson Olefination: Unexpected Rearrangement in the Overcrowded Polycyclic Aromatic Ene Series

“…However, the β‐hydroxysilyl intermediates undergo anti elimination under acidic conditions and syn elimination under basic conditions, so both E and Z isomers can be obtained from a single β‐hydroxysilyl diastereomer 8,9. The final eliminations might proceed either in a stepwise manner10,11 or by a concerted mechanism through the formation of oxasiletanide12 intermediates, although there appears to be overwhelming evidence in support of a stepwise mechanism 4…”

Chemistry of Four-Membered Ring Compounds Containing a Hypervalent Sulfur Atom and a Heteroatom at the Neighbor Positions

“…In the course of our study on four-membered heterocyclic compounds containing highly coordinated main group elements at the position adjacent to the heteroatom, 1 we have succeeded in synthesizing intermediates of the Wittig reaction, 2 the Peterson reaction, 3 and the boron-Wittig reaction. 4 Most of them were isolated as stable compounds by introduction of the Martin ligand.…”