The reaction of some propargyl alcohols with benzeneselenenyl chloride

Abstract

The reaction of benzeneselenenyl chloride with twenty-two propargyl alcohols in methylene chloride solution is reported. Products of both Markownikoff and anti-Markownikoff regiochemistry are formed in an anti stereospecific manner. The regioselectivity or specificity is found to be very dependent upon the nature of the substituents geminal to the alcoholic moiety. In general the presence of bulky substituents geminal to the alcoholic moiety tend to favour formation of the anti-Markownikoff adduct under conditions of kinetic control. The Markownikoff adducts are found to be favoured thermodynamically.

Proton chemical shifts in NMR. Part 16.1 Proton chemical shifts in acetylenes and the anisotropic and steric effects of the acetylene group

“…9-Ethynylanthracene (17) was synthesised by Sonogashira coupling 23 of 9-bromoanthracene and trimethyl-silylacetylene. 1-Ethynyl-t-and -c-4-tert-butylcyclohexan-r-1-ol (7-trans, 7-cis), 2-exo-ethynylbicyclo[2.2.1]heptan-2-ol (8) and 2,2Ј-ethyne-1,2-diylbis(1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol)(9) were synthesised by the addition of ethynylmagnesium bromide to the corresponding ketones in THF 24.…”

Highly Stereoselective One-Pot Procedure To Prepare Bis- and Tris-chalcogenide Alkenes via Addition of Disulfides and Diselenides to Terminal Alkynes

“…The reaction is faster at a high temperature; however, the mixture of Z and E vinylic selenides was obtained in an almost 1:1 ratio (Scheme ) . On the other hand, the eletrophilic addition of organoselenenyl halides to alkynes gave a mixture of Markownikov and anti-Markownikov adducts, depending on the nature of the substituents at the triple bond (Scheme ) . Conversely, vinylic selenides can be prepared by palladium-catalyzed hydroselenation of alkynes to afford the Markownikov adduct in good yields …”