Deoxygenation of dialkyl sulfoxides by dimethylsilylene: Steric requirements

1H chemical shifts in NMR. Part 27: proton chemical shifts in sulfoxides and sulfones and the magnetic anisotropy, electric field and steric effects of the SO bond

“…The chemical shifts for compounds 2, [18] 5, [18] 8, [19] 9, [19] 16, [19] 17, [20] 18, [21] 19, [22] 21, [21] 23, [23] 24, [21] 25, [24] 26 [25] and 27 [25] were taken from the literature. All compounds and solvents used in the analyses for this work were obtained commercially from Sigma-Aldrich Co. Ltd.…”

“…The model of through-bond and through-space effects arising from the SO bonds of these molecules gave good agreement between experimental and calculated chemical shifts. It was necessary to include dibenzothiophene (18) in the study to more accurately model the aromatic ring currents for dibenzothiopheneoxide (21) and dibenzothiophenedioxide (24).…”

Reaction of Dimethyldichlorosilane, Phenylmethyldichlorosilane, or Diphenyldichlorosilane with Dimethyl Sulfoxide. Evidence for Silanone and Cyclodisiloxane Intermediates

“…Dimethylsilanone has been generated by pyrolysis of both D 4 , and 3,3-dimethyl-6-oxa-3-silabicyclo[3,1,0]hexane. , Silanones have often been generated by methods which involve conversion of an initial reactive silicon-containing intermediate into a silanone. For example, dimethylsilene, produced by pyrolysis of 1,1-dimethylsilacyclobutane at ∼500 °C, reacts with non-enolizable ketones such as benzophenone to yield dimethylsilanone. − Photochemically generated dimethylsilylene deoxygenates epoxides, , nitrous oxide, or DMSO , to yield dimethylsilanone and alkenes, nitrogen, or dimethyl sulfide, respectively. Reactive dimethylsilanone is also formed in the low-temperature reactions of DMSO with either 1,1-dimethyl-2,3-bis(trimethylsilyl)-1-silirene or hexamethylsilirane .…”

“…For example, dimethylsilene, produced by pyrolysis of 1,1-dimethylsilacyclobutane at ∼500 °C, reacts with non-enolizable ketones such as benzophenone to yield dimethylsilanone. [7][8][9] Photochemically generated dimethylsilylene deoxygenates epoxides, 10,11 nitrous oxide, 12 or DMSO 13,14 to yield dimethylsilanone and alkenes, nitrogen, or dimethyl sulfide, respectively. Reactive dimethylsilanone is also formed in the lowtemperature reactions of DMSO with either 1,1-dimethyl-2,3-bis(trimethylsilyl)-1-silirene or hexamethylsilirane.…”

A combined kinetic and computational study of the reactions of transient germylenes with oxiranes and thiiranes in solution

“…9,10 Stable silane-and germanethiones have also been prepared by abstraction reactions involving sterically encumbered or donor-stabilized tetrylenes, for example with phenyl isothiocyanate or styrene episulfide 11 as sulfur donors; 12 the desulfurization of sila-and germatetrathiolanes is another commonly used method for the preparation of stable M=S bondcontaining compounds. [13][14][15] Silanones are suspected intermediates in the reactions of transient silylenes with substrates such as N 2 O, [16][17][18][19][20][21] CO 2 , 22 aryl nitrile oxides, 23 aryl-and alkylisocyanates, 11 dialkylsulfoxides, [24][25][26] and oxiranes; [27][28][29][30][31] formal oxygen abstraction from oxiranes has also been found to proceed with transient germylenes in the presence of amines. [32][33][34][35][36] The only tetrylene-derived method for the formation of transient silane-and germanethiones that has been reported is sulfur abstraction from thiiranes.…”