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
Synthesis of Symmetrical and Hybrid Dimeric Steroids by Double Suzuki–Miyaura Cross Coupling of 4-Bromo-3-oxo Steroids and Benzene-1,4-diboronic Acid
作者:Martha C. Mayorquín-Torres、Gerardo I. Santiago-Sampedro、Marcos Flores-Álamo、Martín. A. Iglesias-Arteaga
DOI:10.1055/s-0037-1611484
日期:2019.8
one hybrid dimer in which the steroid cores are connected by a 1,4-phenylene moiety were obtained by double Suzuki–Miyaura cross coupling of benzene-1,4-diboronic acid with 4-bromo-4-en-3-oxosteroids derived from cholesterol and diosgenin. Detailed NMR characterization of the obtained dimers is described. Two symmetrical dimers and one hybrid dimer in which the steroid cores are connected by a 1,4-phenylene
Synthesis of Highly Functionalized Allylic Alcohols from Vinyl Oxiranes and <i>N</i>-Tosylhydrazones via a Tsuji–Trost-Like “Palladium–Iodide” Catalyzed Coupling
作者:Stefano Parisotto、Annamaria Deagostino
DOI:10.1021/acs.orglett.8b03026
日期:2018.11.2
An unprecedented efficient palladium(0)-catalyzed reaction of vinyl oxiranes with N-tosylhydrazones, affording “skipped” allylicalcohols in total regioselectivity and stereoselectivity, with excellent functional-group compatibility, is reported. In this Tsuji–Trost-like allylation, we propose the use of N-tosylhydrazones as a synthetic equivalent of α-styryl anions. More than 20 new products are described
�ber Steroide und Sexualhormone. 155. Mitteilung. �ber 3?, 5-Dioxy-koprostan und zwei epimere 3,4-Dioxy-cholestane
作者:Pl. A. Plattner、H. Heusser、A. B. Kulkarni
DOI:10.1002/hlca.19480310647
日期:——
Durch katalytische Reduktion des Cholestenon-epoxyds ist es gelungen, auf partialsynthetischem Weg 3α, 5-Dioxy-koprostan zu bereiten, das in der räumlichen Anordnung des Asymmetriezentrums 5 der Konfiguration des Strophanthidins und verwandter Aglykone entspricht.