74832-85-2Relevant articles and documents
β-Amyrin Biosynthesis: Effect of Steric Bulk at the 6-, 10- and 15-Positions in the 2,3-Oxidosqualene Backbone on Polycyclisation Cascades
Terasawa, Yuri,Sasaki, Yusuke,Yamaguchi, Yuki,Takahashi, Kazunari,Hoshino, Tsutomu
, p. 287 - 295 (2017/01/24)
β-Amyrin synthase incubation experiments have been conducted to determine the influence of steric effects at the 6-, 10- and 15-positions of 2,3-oxidosqualene on the polycyclisation pathway. Nor- and ethyl-substituted oxidosqualene analogues were synthesised. Cyclisation of the ethyl-substituted analogues did not occur, but the nor analogues underwent a polycyclisation cascade to yield fully cyclised products with 6/6/6/6/6-fused pentacyclic scaffolds generated via a final oleanyl cation. Previously, we reported that 19- and 23-ethyl-substituted analogues underwent polycyclisation reactions. Therefore, the catalytic domain involved in earlier cyclisation steps is notably compact. In contrast, the catalytic domain in the later cyclisation steps is more loosely packed (less compact) to accommodate the bulky ethyl group. The reaction cavities for recognising branched methyl groups are discussed by comparing β-amyrin synthase with other triterpene cyclases such as lanosterol and hopene synthases.
Total synthesis of polyprenylhydroquinols and benzoquinones
Bouzbouz, Samir,Kirschleger, Bernard,Villieras, Jean
, p. 67 - 84 (2007/10/03)
The total synthesis of polyprenylhydroquinols and benzoquinones is described.First, two appropriate aromatic allyl carbonates (moieties with one and two prenyls) and two activated bifunctional terpenyl derivatives (moieties with two and three prenyls) were synthesized.These molecules were then reacted together using a highly regio- and stereoselective coupling with Pd(PPh3)4 as a catalyst.The synthesis was achieved by functional group elimination and formation of quinonic and hydroquinonic moieties. - Keywords: polyprenylbenzoquinol; polyprenylhydroquinone; allylcarbonate; ?-allyl palladium complex
Surface-mediated reactions. 5. Oxidation of sulfides, sulfoxides, and alkenes with tert-butyl hydroperoxide
Breton, Gary W.
, p. 3825 - 3828 (2007/10/02)
Silica gel mediates the reactivity of (CH3)3COOH, affording a convenient, environmentally benign method for oxidizing sulfides, sulfoxides, and alkenes. Electrophilic oxidation of sulfides and alkenes (Scheme 1A) and nucleophilic oxidation of sulfoxides (Scheme 1B) are apparently involved. Basic alumina mediates the oxidation of sulfoxides.
