80663-66-7Relevant academic research and scientific papers
Formation of dihydroxyselenides from allylic alcohols and their conversion to β-hydroxy epoxides via substitution of a phenylselenonyl group
Cooper, Matthew A.,Ward, A. David
, p. 7963 - 7972 (2007/10/03)
Hydroxyselenation of allylic alcohols occurs with high regio- and stereoselectivity to give β,β′-dihydroxyphenylselanyl adducts in high yields. An exception is the reaction of the terminal alcohol, 2-methylprop-2-en-1-ol, which forms only a 1,2-diol product. Generally, the addition is Markovnikov in orientation, but the fact that one anti-Markovnikov addition is observed and that addition to 1,2-disubstituted alkenes shows a strong preference for one regioisomer suggests that an interaction of the allylic alcohol with the selenium atom of the reaction intermediate (which weakens the Cβ-Se bond in the intermediate) is also an important factor in determining the preference for addition of the phenylselanyl group to the double bond carbon nearest the allylic alcohol. The hydroxyselenated adducts of allylic alcohols can be readily converted to β-hydroxy epoxides in good yields via oxidation with m-chloroperbenzoic acid to a selenone and subsequent treatment with base. Hydroxyselenation of crotyl acetate and 3-acetoxycyclohexene is more regiocatholic than hydroxyselenation of the corresponding allylic alcohols. It appears that the known selectivity of additions of phenylselanyl chloride to these acetates in organic solvents is lost when water or a Lewis acid complexes to the acetate group.
Origins of Regio- and Stereoselectivity in Additions of Phenylselenenyl Chloride to Allylic Alcohols and the Applicability of These Additions to a Simple 1,3-Enone Transposition Sequence
Liotta, Dennis,Zima, George,Saindane, Manohar
, p. 1258 - 1267 (2007/10/02)
The regio- and stereoselectivity of phenylselenenyl chloride additions to allylic alcohols and their derivatives have been systematically studied.On the basis of the results, a mechanism involving two basic premises is proposed.These are as follows: (a) allylic oxygen's direct selenonium ion formation to the syn face of the double bond; (b) axial attack of the chloride ion is kinetically favored over equatorial attack.A series of rules which are useful for predicting the regio- and stereoselectivity of phenylselenenyl chloride additions to allylic systems are discussed.In addition, these reactions can be used as the key step in a general 1,3-enone transposition sequence.Several examples of this transposition sequence are illustrated.
