Cameroonane, Prenopsane and Nopsane, Three New Tricyclic Sesquiterpene Skeletons

Antibacterial activity of selected Cameroonian dietary spices ethno-medically used against strains of Mycobacterium tuberculosis

“…Two new lignans together with the known lupeol and sitosteryl ß-D-glucopyranoside, have been isolated from the roots of E. giganteus var. lelyi C. D. Adams Compositae) (Tene et al, 2004); Sesquiterpenoids have been previously isolated from the essential oil (Menut et al, 1997;Weyerstahl et al, 1998). However, there are no previous reports on the antituberculosis activity and chemical nature of the antituberculosis compounds in E. giganteus.…”

Biosynthesis and Chemical Synthesis of Presilphiperfolanol Natural Products

“…[1,13] Tricyclic alcohol 1 and β-caryophyllene ( 14 ) (Figure 4) were also isolated from the same natural sources in numerous reports. [9,14] These findings suggested that three classes of polycyclic sesquiterpenes were connected in a common biosynthetic pathway. In 1980, Bohlmann explained these results by proposing that farnesyl pyrophosphate (FPP) ( 21 ) undergoes enzymatic polycyclization to caryophyllenyl cation 23 (Scheme 1A).…”

“…Presilphiperfol-7(8)-ene ( 6 ) [9] presumably arises from the deprotonation of presilphiperfolanyl cation intermediates. Natural products such as the britanlins ( 7 – 9 ) [10] display additional oxidation at primary carbons in the presilphiperfolane skeleton.…”

Cycloadditions of Allylsilanes - Part 22.¹ Stereoselective Synthesis of Cyclopentanes and Cyclobutanes by Lewis Acid Promoted [3+2] and [2+2] Cycloadditions of Allylsilanes

“…112,118 We discovered that this ratio can be improved in favor of the natural compound (±)-69 using diisobutylaluminum hydride at low temperatures. 120,123 Thus, products (±)-69 and (±)-epi-69 were obtained in a ratio of 3.7:1.…”