5847-18-7Relevant academic research and scientific papers
Catalytic, transannular carbonyl-olefin metathesis reactions
Nasrallah, Daniel J.,Riehl, Paul S.,Schindler, Corinna S.
, p. 10267 - 10274 (2019/11/20)
Transannular carbonyl-olefin metathesis reactions complement existing procedures for related ring-closing, ring-opening, and intermolecular carbonyl-olefin metathesis. We herein report the development and mechanistic investigation of FeCl3-catalyzed transannular carbonyl-olefin metathesis reactions that proceed via a distinct reaction path compared to previously reported ring-closing and ring-opening protocols. Specifically, carbonyl-ene and carbonyl-olefin metathesis reaction pathways are competing under FeCl3-catalysis to ultimately favor metathesis as the thermodynamic product. Importantly, we show that distinct Lewis acid catalysts are able to distinguish between these pathways to enable the selective formation of either transannular carbonyl-ene or carbonyl-olefin metathesis products. These insights are expected to enable further advances in catalyst design to efficiently differentiate between these two competing reaction paths of carbonyl and olefin functionalities to further expand the synthetic generality of carbonyl-olefin metathesis.
LEAD TETRAACETATE OXIDATION OF (Z)- AND (E)-5,10-SECOCHOLEST-1(10)-ENE-3β,5α-DIOL 3-ACETATE
Mihailovic, Mihailo Lj.,Kruscic, Natalija,Pavlovic, Vladimir,Lorenc, Ljubinka
, p. 1095 - 1100 (2007/10/02)
The lead tetraacetate oxidation of (Z)-5,10-secocholest-1(10)-ene-3β,5α-diol 3-acetate (1) gave products arising from: (i) conversion of the 5α-hydroxy group to the ketone function (2), (ii) intramolecular cyclization (to the 2α,5α-tetrahydrofurane-type ether 3), and (iii) allylic acetoxylation at the C(9) position (3 and 4), while similar oxidation of (E)-5,10-secocholest-1(10)-ene-3β,5α-diol-3-acetate (5) afforded mainly the product formed by conversion of 5α-OH to the keto-carbonyl group (6).
Conformations of the Ten-membered Ring in 5,10-Secosteroids. III: (Z)-3β- and (Z)-3α-Hydroxy-5,10-seco-1(10)-cholesten-5-one Esters and (Z)-5,10-seco-1-(10)-Cholestene-3,5-dione
Fuhler, Hermann,Lorenc, Ljubinka,Pavlovic, Vladimir,Rihs, Grety,Rist, Guenther,et al.
, p. 703 - 715 (2007/10/02)
(Z)-3β-Acetoxy- and (Z)-3α-acetoxy-5,10-seco-1(10)-cholesten-5-one (6a) and (7a) were synthesized by fragmentation of 3β-acetoxy-5α-cholestan-5-ol (1) and 3α-acetoxy-5β-cholestan-5-ol (2), respectively, using in both cases the hypoiodite reaction (the lea
Synthesis, Structure, and Reactions of Secosteroids containing a Medium-sized Ring. Part 17. Structure-Reactivity Relationship in the Solvolysis of 5,10-Secosteroidal 3-Tosylates
Lorenc, Ljubinka,Gasic, Miroslav J.,Juranic, Ivan,Dabovic, Milan,Mihailovic, Mihailo Lj.
, p. 1356 - 1365 (2007/10/02)
Kinetic measurements of the solvolysis of (Z)-3α- and (Z)-3β-, and (E)-3α- and (E)-3β-tosyloxy-5,10-secocholest-1(10)-en-5-ones in buffered aqueous acetone (90 : 10 v/v) reveal that the (Z)-3α, (E)-3α-, and (E)-3β-tosylates are solvolysed according to a first-order rate law (the relative rates being ca. 1 : 3 : 8), while the (Z)-3β-ester, under the same conditions, reacts at a much slower rate by a complex mechanism, the kinetics of which are best approximated by a second-order law.These data and product analysis indicate that the former three esters are solvolysed with considerable double bond participation , and that this interaction is unimportant for the (Z)-3β-tosylate.On the basis of conformational analysis of the starting tosylates and stereoelectronic requirements for homoallylic interaction, a possible mechanistic pathway for these solvolyses is proposed.
