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
The organoselenium-mediated reduction of α,β-epoxy ketones, α,β-epoxy esters, and their congeners to β-hydroxy carbonyl compounds: Novel methodologies for the synthesis of aldols and their analogues
Novelmethods for the reduction of α,β-epoxy ketones, α,β-epoxy esters (glycidic esters), and their congeners to β-hydroxy carbonyl compounds (aldols) by the use of organoselenium reagents are described. The reagents, a sodium phenylseleno(triethyl)borate complex Na[PhSeB(OEt)3] easily prepared by reduction of (PhSe)2 with NaBH4 in EtOH and benzeneselenol (PhSeH) generated in situ from the borate complex
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.
Oxyfunctionalized testosterone: CglUPO, a novelperoxygenasefrom the ubiquitous ascomycetous fungus C. globosum, facilitates the direct incorporation of epoxy and hydroxy functionalities into the sterically demanding molecule testosterone. The reaction requires only hydrogen peroxide as co‐substrate. This peroxygenase and related enzymes might be useful tools for the synthesis of pharmaceutically