3964-63-4Relevant articles and documents
Total synthesis of (+)-myriocin and (-)-sphingofungin E from aldohexoses using overman rearrangement as the key reaction
Oishi, Takeshi,Ando, Koji,Inomiya, Kenjin,Sato, Hideyuki,Iida, Masatoshi,Chida, Noritaka
, p. 1927 - 1947 (2007/10/03)
Total synthesis starting from aldohexoses of naturally occurring α-substituted α-amino acids, (+)-myriocin (1) and (-)-sphingofungin E (2), is described. Overman rearrangement of allylic trichloroacetimidate 6E derived from D-mannose effectively generated the tetrasubstituted carbon with nitrogen, and subsequent Wittig olefination afforded the highly functionalized moiety 3 of myriocin stereoselectively. Sulfone-mediated coupling reaction of the allyl bromide 3 with C12 hydrophobic part 4 successfully constructed the carbon framework possessing E-olefin 28. Removal of the sulfone and protecting groups completed the chiral and stereoselective total synthesis of (+)-myriocin (1). A similar transformation starting from D-glucose also accomplished the total synthesis of (-)-sphingofungin E (2).
MECHANISM OF THE γ-RADIOLYSIS OF 2-PROPANOL SOLUTIONS OF CYCLOHEXANONES
Alipour, E.,Vidril, D.,Micheau, J. C.,Paillous, N.,Lattes, A.,et al.
, p. 2807 - 2814 (2007/10/02)
The γ-radiolysis of 2-propanol solutions of cyclohexanone gives mainly hydrogen, acetone, pinacol, methane derived from 2-propanol, and cyclohexanol, 2-(2-cyclohexanonyl)-cyclohexanone, and 3-(2-hydroxy-2-propyl)cyclohexanone derived from cyclohexanone.The radiolytic yields of all these products were highly dependent on the initial cyclohexanone concentration.The formation of cyclic alcohols by radioreduction has been extended to various substituted cyclohexanones.Radiolytically generated solvated electrons are scavenged by cyclohexanone, leading to the corresponding radical anions.The protonation of these radical anions gives rise to cyclohexanol via the dismutation of the hydroxycyclohexyl radicals.Steady state radiolysis measurements were complemented by pulse radiolysis in dilute solution.It was established that radical-anions and hydroxylated radicals decayed according to a second order rate law.When ketone concentration was lower than 0.1M, radiolytic yields were in agreement with the mechanism mentioned above.However, in concentrated media the large increase in G(cyclohexanol) cannot be only accounted for by the involvement of radiolytically generated solvated electrons; probably it is due to an electron transfer from the cyclohexanone enolate to cyclohexanone itself, thus generating extra amounts of cyclohexanone radical anions.
