14252-46-1

It has been found that the reactions of sulfoxides bearing hydrogen(s) at the α-position (R 1 SOCHR 2R 3: R 1 = alkyl or Ph; R 2 = H, alkyl, or Ph; R 3 = H or Me) with thiols (R 4SH: R 4 = alkyl or aryl) in the presence of the (diisopropylamino)magnesium

Enol ethers are reacted with mercaptanes to give the corresponding O/S- or S/S-acetals in medium to high yield. Either product can be formed selectively depending on the acid catalyst and the reaction time applied.

The mixed cuprates, generated by reductive lithiation of bis(phenylthio)acetals using lithium 4,4'-di-tert-butylbiphenylide (LDBB), followed by addition of cuprous bromide-dimethyl sulfide complex, undergo conjugate addition to enones in the presence of t

Aldehydes and acetals were very efficiently converted to acyclic and cyclic dithioacetals in 5 M lithium perchlorate/diethyl ether (LPDE) medium at ambient temperature in high yields.Spectroscopic and other experimental evidences strongly suggest the formation of oxocarbenium ion intermediates from acetals in 5 M LPDE which subsequently reacted with thiols to give the dithioacetals.Under the same conditions ketones and their acetals also reacted, albeit very slowly compared to aldehydes and acetals, to yield dithioacetals.The difference in their reactivity was successfully employed in the chemoselective dithioacetalization of aldehydes and acetals in the presence of ketones and their acetals.The chemoselective dithioacetalization of keto aldehydes has been realized with the keto group remaining intact.The present method offers a convenient, efficient, and neutral medium for the deprotection of acetals to aldehydes and also the chemoselective protection of aldehydes to dithioacetals.

γ-Trialkylstannyl ketones underwent cyclobutanation, C-C bond cleavage, or 1,5-hydride shift, depending upon the substitution pattern of the substrates.

The α-phenylthiosilanes (2) have been used to prepare the α-silyl anions (1) by reaction with lithium naphthalenide; subsequent condensation with a carbonyl compound gave the alkene (8) via the Peterson reaction.The α-phenylthiosilanes (2) were prepared from n,n-bis(phenylthio)acetals (4) by reaction with lithium naphthalenide and chlorotrimethylsilane.The n,n-bis(phenylthio)acetals (4) were obtained, in turn, from 1,1-bis(phenylthio)acetals (5) by anion formation with butyl-lithium-N,N,N',N'-tetramethylethylenediamine complex in hexane followed by reaction with an alkyl halide.The Peterson reaction was also used to prepare vinyl sulphides (9) and vinyl sulphones (13).

Reactions of diethylaluminium thiophenoxide (Et2AlSPh) with acetals of several types, in which acyclic, cyclic, and bicyclic ones are involved, were examined in comparison with the known reaction using thiophenol in the presence of Lewis acid and found to provide a new and efficient method for preparation of monothioacetals.

A particularly convenient method for the preparation of α-lithiosilanes consists of the reductive lithiation of diphenyl thioacetals or thioketals with lithium 1-(dimethylamino)naphthalenide, treatment of the resulting anion with trimethylsilyl chloride,

Bis(phenylthio)acetals can be lithiated with n-butyllithium - N,N,N'N'-tetramethylethylenediamine complex in hexane and consequently alkylated.