A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalyticall...A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalytically asymmetric Pictet-Spengler cyclization/lactamization cascade reaction generating the key tetracyclic lactam skeleton;(b)asymmetricα-alkylation of carbonyl group induced by Evans'chiral auxiliary with excellent diastereoselectivity;(c)a highly efficient one-pot desulfurization/hydrogenation/debenzylation transformation using Raney Ni under hydrogen atmosphere;as well as(d)an intramolecular Vorbürggen reaction constructing the quaternary ammonium motif and the final cagelike skeleton.展开更多
One of the largest subfamilies within the famous Daphniphyllum alkaloid family is made up of the yuzurimine-type(or macrodaphniphyllamine-type) alkaloids. Their complex aza-polycyclic caged structures, several contigu...One of the largest subfamilies within the famous Daphniphyllum alkaloid family is made up of the yuzurimine-type(or macrodaphniphyllamine-type) alkaloids. Their complex aza-polycyclic caged structures, several contiguous stereogenic centers, and vicinal all-carbon quaternary centers make these alkaloids formidable challenge for synthetic chemists. Recently, synthesis of these alkaloids has received extensive attention from our community. Herein, we wish to report the total synthesis of C_(14)–epideoxycalyciphylline H, a putative member of yuzurimine-type alkaloid subfamily. Key transformations employed in our approach include an intramolecular Prins reaction and a Pd-catalyzed enyne cycloisomerization. In addition, synthesis of a daphnezomine L-type alkaloid, paxdaphnidine A, was also studied.展开更多
The content of CPT and VCS-LT could be improved to 4.88%, 21.52%, respectively from 0.379%, 1.524% in crude extract solution after refined by X-5 resin. Then the refined solution was chromatographically separated with...The content of CPT and VCS-LT could be improved to 4.88%, 21.52%, respectively from 0.379%, 1.524% in crude extract solution after refined by X-5 resin. Then the refined solution was chromatographically separated with hypercrosslinked resin and the contents of VCS-LT could be improved to about 60%(CPT 15%). The achromaticity needle crystal was obtained after several recrystallization and its structure was confirmed by IR, 1H NMR, 13C NMR, MS and element analysis.展开更多
基金supported by Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation,CAMS Innovation Fund for Medical Sciences(CIFMS,No.2022-I2M-3–002)。
文摘A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalytically asymmetric Pictet-Spengler cyclization/lactamization cascade reaction generating the key tetracyclic lactam skeleton;(b)asymmetricα-alkylation of carbonyl group induced by Evans'chiral auxiliary with excellent diastereoselectivity;(c)a highly efficient one-pot desulfurization/hydrogenation/debenzylation transformation using Raney Ni under hydrogen atmosphere;as well as(d)an intramolecular Vorbürggen reaction constructing the quaternary ammonium motif and the final cagelike skeleton.
基金the National Natural Science Foundation of China (Nos.21971104 and 22271136)Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis (No.ZDSYS20190902093215877)+4 种基金Guangdong Provincial Key Laboratory of Catalysis (No.2020B121201002)Guangdong Innovative Program (No.2019BT02Y335)Education Department of Guangdong Province, Key research projects in colleges and universities in Guangdong Province (No.2021ZDZX2035)Shenzhen Nobel Prize Scientists Laboratory Project (No.C17783101)Innovative Team of Universities in Guangdong Province (No.2020KCXTD016)。
文摘One of the largest subfamilies within the famous Daphniphyllum alkaloid family is made up of the yuzurimine-type(or macrodaphniphyllamine-type) alkaloids. Their complex aza-polycyclic caged structures, several contiguous stereogenic centers, and vicinal all-carbon quaternary centers make these alkaloids formidable challenge for synthetic chemists. Recently, synthesis of these alkaloids has received extensive attention from our community. Herein, we wish to report the total synthesis of C_(14)–epideoxycalyciphylline H, a putative member of yuzurimine-type alkaloid subfamily. Key transformations employed in our approach include an intramolecular Prins reaction and a Pd-catalyzed enyne cycloisomerization. In addition, synthesis of a daphnezomine L-type alkaloid, paxdaphnidine A, was also studied.
文摘The content of CPT and VCS-LT could be improved to 4.88%, 21.52%, respectively from 0.379%, 1.524% in crude extract solution after refined by X-5 resin. Then the refined solution was chromatographically separated with hypercrosslinked resin and the contents of VCS-LT could be improved to about 60%(CPT 15%). The achromaticity needle crystal was obtained after several recrystallization and its structure was confirmed by IR, 1H NMR, 13C NMR, MS and element analysis.
