The azidomethylene protecting group allows the synthesis of unstable phenolic compounds which are used as quinonemethideprecursors in the alkylations of alcohols, phenols, azide, thiophenol, amines, enols and enolates.
N-Fluoropyridinium salts provide a new system of fluorinatingagents by which a wide range of nucleophilic substrates differing in reactivity can be fluorinated due to the varying degree of fluorinating power and also fluorinated very selectively through structural alteration. The scope of selective fluorination should be broadened considerably on the basis of the present results. The N-fluoropyridinium
Totalsynthese optisch aktiver Steroide, IX. Darstellung und Strukturuntersuchung diastereomerer 4,8,14‐Androstatrien‐3,17‐dione
作者:Jürgen Ruppert、Ulrich Eder、Rudolf Wiechert
DOI:10.1002/cber.19731061123
日期:1973.11
Optisch aktives (+)-8,14-Seco-4,9(11)-androstadien-3,14,17-trion (8) und (+)-8,14-Seco-4,8-androstadien-3,14,17-trion (10) wird zu 13ξ-Androsta-4,8,14-trien-3,17-dion (9) cyclisiert. Es wurde lediglich eine geringe Induktion von einem chiralen Zentrum am Kohlenstoffatom C-10 zum neu gebildeten Zentrum am Kohlenstoffatom C-13 beobachtet.
作者:Andrzej Robert Daniewski、Teresa Kowalczyk-Przewloka
DOI:10.1016/s0040-4039(00)87355-4
日期:1982.1
The coupling of m-methoxystyrene () and diazoketone () over copper tartarate gave optically active (46% ee) cyclopropyl derivative (), which was converted into compounds or with 22% of optical induction.