Effect of trimethylsilyl groups on Beckmann rearrangements and fragmentations

Mono-deoxygenation of Nitroalkanes, Nitrones, and HeterocyclicN-Oxides by Hexamethyldisilane through 1,2-Elimination: Concept of “Counterattack Reagent”

“…Furthermore, we treated hexamethyldisilane with methyllithium in HMPA−THF at 0 °C to generate Me 3 SiLi . In situ, we allowed Me 3 SiLi (∼1.1 equiv) to react with nitrones 11a − 15a at −78 °C for 20 min and at room temperature for 4−6 h (Scheme ).…”

“…This concept was also applied in a direct syntheses of ketene thioacetals and 2-trimethylsilyl-1,3-dithiane derivatives from 1,3-dithiane and a source of trimethylsilyl anion as well as halotrimethylsilanes …”

Climbing Back up the Nucleophilic Reactivity Scale. Use of Cyclosila Derivatives as Reactivity Boosters in Anionic Polymerization

“…However, a definite period of mixing is really necessary. It has been noted in the literature that nucleophilic reactions of the silyl anions in HMPA are often accompanied by electron-transfer processes, leading to formation of side products. ,, In addition, Hudrlik et al mentioned that (CH 3 ) 3 SiLi reacted with (CH 3 ) 3 SiSi(CH 3 ) 3 to give (CH 3 ) 3 Si(CH 3 ) 2 SiLi, and the model reaction of 1,1,2,2-tetramethyl-1,2-disilacyclopentane with equimolar or excess amounts of trimethylsilyl anion under various conditions resulted in failure to isolate the expected 1:1 adduct, (i.e. (CH 3 ) 3 Si(CH 3 ) 2 Si(CH 3 ) 3 (CH 3 ) 2 SiLi) …”

Silicon assisted diversified reaction of a β-silylmethylene malonate with dimethylsulfoxonium methylide

“…This stabilizing effect also plays an important role in directing the regioselectivity in various organic reactions. Some recent examples include Baeyer-Villiger oxidation [16], Bamford-Stevens reaction [17], Beckmann fragmentation [18,19], Curtius reaction [20], Norrish types I and II cleavages [21,22], palladium-catalyzed nucleophilic substitution [23], Nazarov cyclizations [24,25], decarboxylation reactions [26] and stereospecific 1,2-silyl shifts [27,28]. The propensity of b-elimination of organosilicon compounds was first demonstrated by Peterson [29,30] for olefin synthesis.…”