79719-89-4Relevant academic research and scientific papers
Alkynyl Phenyl Selenides as Convenient Precursors for the Synthesis of Stereodefined Trisubstituted Alkenes
Tingoli, Marco,Tiecco, Marcello,Testaferri, Lorenzo,Temperini, Andrea,Pelizzi, Giancarlo,Bacchi, Alessia
, p. 4691 - 4700 (2007/10/02)
The addition of p-toluenesulfonic acid to alkynyl phenyl selenides is regio- and stereospecific and affords (Z)-α-(phenylseleno)vinyl p-toluenesulfonates in good yield. α-(Phenylseleno)vinyl halides are obtained from the reactions of these compounds with magnesium halides.The reactions of (Z)-α-(phenylseleno)vinyl p-toluenesulfonates with cyanocuprates afford the corresponding trisubstituted alkenes in which the tosyl group has been selectively substituted by an aryl or an alkyl group with retention of configuration.Finally, the cross coupling reaction of these vinyl selenides with methylmagnesium bromide, in the presence of a nickel catalyst, occurs with retention of configuration and affords the selenium free trisubstituted alkenes.
Preparation of Allenic Sulfones and Allenes from the Selenosulfonation of Acetylenes
Back, Thomas G.,Krishna, M. Vijaya,Muralidharan, K. Raman
, p. 4146 - 4153 (2007/10/02)
β-(Phenylseleno)vinyl sulfones 2 are readily obtained from the free-radical selenosulfonation of acetylenes.Compounds 2 isomerize to allyl sulfones 4 under base-catalyzed conditions in nearly quantitative yield, with high stereoselectivity favoring the Z configuration.Allyl sulfones 4 afford generally high yields of allenic sulfones 1 when subjected to oxidation with m-chloroperbenzoic acid or tert-butyl hydroperoxide, followed by selenoxide syn-elimination.The sulfone-stabilized anion intermediates in the isomerizations of 2 to 4 can be alkylated, deuterated,or silylated in the α-position prior to oxidation, providing allenic sulfones with an additional α-substituent.In some cases, spontaneous elimination of the phenylseleno group occurred, producing the allenic sulfone without the need for an oxidation step.Desulfonylation of allyl sulfones 4f, 4c, and 25 with sodium amalgam afforded vinyl selenides that were converted to allenes in moderate to good yields by oxidation-elimination.The copper catalyzed coupling of allyl sulfones 4 with Grignard reagents comprises an alternative route to vinyl selenide precursors of allenes.These procedures permit the synthesis of various α- and γ-substituted allenic sulfones and allenes from acetylenes.
