35953-54-9Relevant articles and documents
Stereospecific Reductive Desulfurization of Vinyl Sulfoxides with tert-Butyllithium and an Internal Proton Source
Theobald, Paula G.,Okamura, William H.
, p. 741 - 750 (2007/10/02)
Trienyl and allenyl phenyl sulfoxides can be reduced stereospecifically with retention of configuration in good yields using tert-butyllithium with methanol (MeOH) as an internal (in situ) proton source.The method can be easily modified to give stereospecifically deuterium-labeled compounds.While simple monoene sulfoxides afford attenuated yields of reduced olefin, the method is useful for the reduction of more sensitive and complex polyene sulfoxides as exemplified by the reduction of trienyl sulfoxides 2b, 3b, 9 and allenyl sulfoxide 10 and by a brief review of additional examples which have emerged from this laboratory.That the reduction proceeds through the direct protonation of sulfurane intermediates such as 35 or 35' is an attractive mechanistic hypothesis, but several other possibilities exist.A pathway involving a vinyllithium as a reactive intermediate is considered to be less likely.
ON THE STEREOSPECIFIC REDUCTION OF VINYLSULFOXIDES WITH THE POSSIBILITY OF DEUTERIUM LABELING
Theobald, Paula G.,Okamura, William H.
, p. 6565 - 6568 (2007/10/02)
Upon treating triene sulfoxide 2 or 3 in the presence of methanol (internal proton source) in ether with tert-butyllithium, the reduced product 4b or 4c, respectively, is obtaned with retention of configuration.A deuterium label can be incorporated by using methanol-d1 as the internal proton source.
Oxidation of Alkyl Phenyl Selenides, Tellurides, and Telluroxides with meta-Chloroperbenzoic Acid for a Facile and Novel Transformation of C-Se and C-Te Bonds to C-O Bonds
Uemura, Sakae,Fukuzawa, Shin-ichi
, p. 471 - 480 (2007/10/02)
In sharp contrast to the well-known selenoxide elimination leading to olefins, the treatment of alkyl phenyl selenides (PhSeR) with an excess of meta-chloroperbenzoic acid (MCPBA; 2-5 equiv. to a selenide) in alcohol at room temperature affords the corresponding dialkyl ethers by the substitution of a phenylselenium (PhSe) moiety with an alkoxy group.A similar reaction proceeds by using alkyl phenyl tellurides (PhTeR) and telluroxides , a facile substitution of PhTe or PhTe(O) moiety by an alkoxy group being observed.Methanol is the most appropriate solvent for these oxidations and alkyl methyl ethers are formed in excellent yields.The reaction is accompanied by phenyl migration when applied to some selenides, tellurides, and telluroxides having a phenyl group at a vicinal position to the PhSe, PhTe, or PhTe(O) moiety.Application to the methoxyselenation and methoxytelluration products of cyclohexene and cycloheptene results in a ring-contraction to afford the dimethyl acetals of cyclopentane- and cyclohexane-carbaldehyde, respectively.In case of an allylic phenyl selenide, a sigmatropic rearrangement giving a rearranged allylic alcohol occurs in much preference to the substitution by the methoxy group.Other oxidizing agents than MCPBA such as NaIO4, H2O2, t-BuOOH, and ozone are generally ineffective under similar conditions.It is proposed that the reaction mainly takes place as follows.Alkyl phenyl selenone, alkyl phenyl tellurone, or the MCPBA addition product to them is formed as a reactive intermediate in which an alkyl C-Se or alkyl C-Te bond fission occurs heterolytically by a nucleophilic attack of alcohol, sometimes accompanied by a 1,2-shift of the β-substituent, i.e., phenyl migration and ring-contraction.
