Highly efficient epoxidation of unsaturated steroids using magnesium bis(monoperoxyphthalate) hexahydrate
作者:João F.S. Carvalho、M. Manuel Cruz Silva、M. Luisa Sá e Melo
DOI:10.1016/j.tet.2009.01.100
日期:2009.4
Fast generation of epoxides from the corresponding homoallylic and allylic steroidal olefins was developed by using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) as oxidant suspended in acetonitrile (CH3CN) at reflux temperature. The protocol involves the use of a safe readily available oxidant along with an easy work-up, which renders the process very efficient. Selective 4,5- and 5,6-epoxidations
Diastereoselective epoxidation of olefins by organo sulfonic peracids, II
作者:R. Kluge、M. Schulz、S. Liebsch
DOI:10.1016/0040-4020(95)01128-5
日期:1996.2
have investigated the behaviour of sulfonic peracids 2in situ generated towards olefins 7a,7b,9,11,14,16,18, allylic and homoallylic alcohols 20,22,24,26,28,30,33 and α,β-unsaturated ketones 35,37,39. Generally, the epoxidation proceeds in a peracid-like manner with greater diastereoselectivity than those by common oxidants. In particular, the epoxidation of Δ4 3-ketosteroids 39a-i led to 4α,5α-epoxides
Lithium naphthalenide induced reductive cleavage of α,β-epoxy ketones: an efficient procedure for the preparation of β-hydroxy ketones
作者:Renata Jankowska、Hsing-Jang Liu、George L. Mhehe
DOI:10.1039/a904646a
日期:——
Lithium naphthalenide presents itself as a mild and efficient reagent for the cleavage of α,β-epoxy ketones to give the corresponding β-hydroxy ketones in good yields.
The stereochemistry of the Grignard reaction of steroidal 4,5-epoxy-3-ketones
作者:Cavit Uyanik、Aslihan Malay、Azra S. Ayna、James R. Hanson、Peter B. Hitchcock
DOI:10.1016/j.steroids.2004.09.002
日期:2005.2
The stereochemistry of the addition of methylmagnesium bromide to a steroidal 4,5-epoxy-3-ketone has been shown to be determined by the stereochemistry of the epoxide. The epoxidation to the corresponding 3-alkyl-3-hydroxy-4-enes by per-acid was determined by the stereochemistry of the allylic alcohol.
Identification of a Fossil Sterane Biomarker in Crude Oil - an Androstane with a Modified Carbon Skeleton
作者:Matthias Bender、Marc Schmidtmann、Jürgen Rullkötter、Roger E. Summons、Jens Christoffers
DOI:10.1002/ejoc.201300788
日期:2013.9
of four stereoisomers of 3-methyl-A-nor-androstane (4 % overall yield) was prepared by ionic hydrogenation of the olefin after A-ring recyclization in three steps. 17-Methyl-18-nor-androstane was synthesized in four steps as a mixture of isomers (58 % overall yield) from dihydrotestosterone with a Wagner–Meerwein shift of the 13β-methyl group to C-17 as the key step. Pure 17β- and 17α-methyl-18-nor-13α-androstane