We describe a cerium‐catalyzed aerobic oxidative ringexpansion for the expedient construction of synthetically challenging macrolactones under visible‐light conditions. Cyanoanthracene has been employed as co‐catalyst to accelerate the turnover of the cerium cycle leading to a fast conversion within 20 min of irradiation. Taking advantage of the high efficiency and operationally simple conditions
Stereospecificannulation of hydroxyvinylethers in the presence of triflic anhydride and tertiary amines and its syntheticapplication are described. Each 1-hydroxy-2-oxabicyclo[n.4.0]alkane, 2-oxabicyclo[n.4.0]alk-1(6)-ene and 2-oxabicyclo[n.4.0]alk-1(6+n)-ene is stereoselectively synthesized from the same hydroxyvinylether depending on the choice of the reaction conditions (temperature, solvent
描述了在三氟甲磺酸酐和叔胺存在下的羟基乙烯基醚的立体定向环氧化及其合成应用。每个1-羟基-2-氧杂双环[n.4.0]烷烃,2-氧杂双环[n.4.0] alk-1(6)-烯和2-氧杂双环[n.4.0] alk-1(6 + n)-烯根据反应条件(温度,溶剂和叔胺)的选择,由相同的羟基乙烯基醚立体选择性地合成。这些化合物导致多官能化的环状化合物和一些天然产物。我们提出,这种环化反应是通过纯S N 2样机理进行的。
Highly regio- and stereo-selective annulation–elimination reactions of 1-cycloalkenyl 3-hydroxypropyl ethers
Highly regio- and stereo-selective annulationâelimination reactions of 1-cycloalkenyl 3-hydroxypropyl ethers in the presence of triflic anhydride and tertiary amines are described; the bicyclic vinyl ethers produced are converted to 2-substituted δ-lactones, macrocyclic oxolactones and bicyclic hydroxy ethers by ozonolysis and stereoselective hydroboration.
Verfahren zur Herstellung von makrocyclischen Ketolactonen
申请人:HÜLS AKTIENGESELLSCHAFT
公开号:EP0098367A2
公开(公告)日:1984-01-18
Die Erfindung betrifft ein Verfahren zur Herstellung makrocyclischer Ketolactone der Formel
mit n = 6 bis 12, m = 0 bis 3 und R, und R2 = H, C1-C4-Alkyl, wobei die entsprechenden bicyclischen Enolether mit einem Gemisch aus wäßrigem Wasserstoffperoxid und Ameisensäure behandelt werden.
Combinatorial libraries of polyketides can be obtained by suitable manipulation of a host modular polyketide synthase gene cluster such as that which encodes the PKS for erythromycin. The combinatorial library is useful as a source of pharmaceutically active compounds. In addition, novel polyketides and antibiotics are prepared using this method.