Development and Application of New Transformations of Organosulfur Compounds Utilizing Magnesium Amides

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It was found that sulfoxides bearing hydrogens at the alpha-position only (RSOCH_2R^1) reacted with the tetramethylpiperidinomagnesium reagent, which was generated in situ by treatment of 2,2,6,6-tetramethylpiperidine with ethylmagnesium bromide in refluxing diethyl ether, at room temperature to produce the corresponding dithioacetals (RSCHR^1SR). The treatment of sulfoxides bearing hydrogens both at the alpha- and beta-positions (RSOCHR^1CHR^2R^3) with the magnesium amide was found to afford the corresponding vinyl sulfides (RSCR^1=CR^2R^3) accompanying the corresponding dithioacetals. The pathways leading to the products involving the formation of the sulfur stabilized carbonium ion intermediates were elucidated, and these reactions were extended to syntheses of a range of organosulfur compounds.The reaction of sulfoxides bearing alpha-hydrogen (s) (RSOCHR^1R^2) with the diisopropylaminomagnesium reagent, which was generated in situ by the treatment of diisopropylamine with an excess … More amount of appropriate Grignard reagents (R^3MgBr), resulted in the formation of the corresponding sulfides (RSCR^1R^2R^3). Optically active sulfides could be obtained up to 75% e.e. by using optically active sulfoxides or secondary amines.The (diisopropylamino) magnesium reagent, generated from diisopropylamine and ethylmagnesium bromide, was treated with thiols (R^4SH) prior to the interaction with sulfoxides bearing hydrogen (s) at the alpha-position (R^1SOCHR^2R^3) to afford unsymmetrical dithioacetals (R^1SCR^2R^3SR^4).The treatment of vinyl sulfoxides (PhSOCHR^1=CHR^2) with (dialkylamino) magnesium reagents, generated from secondary amines (R^3_2NH) and ethylmagnesium bromide, proved to give unsymmetrical beta- (N,N-dialkylamino) dithioacetals [(PhS) _2CHR^1CHR^2NR^3_2]. The reaction in the presence of an appropriate thiol (R^4SH) lead to the formation of the corresponding unsymmetrical beta- (N,N-dialkylamino) dithioacetals [(PhS) (R^4S) CHR^1CHR^2NR^3_2].Tretment of the (diisopropylamino) magnesium reagent with enemines, derived from various ketones and aldehydes, prior to the interaction with sulfoxides bearing alpha-hydrogens gave the corresponding alpha- (alpha-alkylthio) alkylated ketones and aldehydes. Less