Total Synthesis of Hapalindole-Type Natural Products
摘要:
AbstractA unified and bioinspired oxidative cyclization strategy was used in the first total syntheses of naturally occurring 12‐epi‐hapalindole Q isonitrile, hapalonamide H, deschloro 12‐epi‐fischerindole I nitrile, and deschloro 12‐epi‐fischerindole W nitrile, as well as the structural revision of the latter. Hapalindoles H and Q were also synthesized.
Stereodivergent Total Synthesis of Hapalindoles, Fischerindoles, Hapalonamide H, and Ambiguine H Alkaloids by Developing a Biomimetic, Redox-Neutral, Cascade Prins-Type Cyclization
作者:Samrat Sahu、Beauty Das、Modhu Sudan Maji
DOI:10.1021/acs.orglett.8b02804
日期:2018.10.19
redox-neutral, Brønsted acid-catalyzed cascade Prins-type cyclization between indole and aldehyde is described to access several structurally diverse indole terpenoid scaffolds in a single step. Applying this concept, stereodivergent total syntheses of nine hapalindole-type alkaloids are accomplished. Key transformations include allylation using geometrically isomeric allylboronic acid followed by a
Enantiospecific Total Syntheses of (+)-Hapalindole H and (−)-12-<i>epi</i>
-Hapalindole U
作者:Dattatraya H. Dethe、Saikat Das、Vijay B. Kumar、Nisar A. Mir
DOI:10.1002/chem.201800970
日期:2018.6.26
Enantiospecific total syntheses of (+)‐hapalindole H and (−)‐12‐epi‐hapalindole U as well as the formal syntheses of (+)‐hapalindole Q and (+)‐12‐epi‐fischerindole U isothiocyanate have been described. Key steps of our approach feature expedient, highly regio‐ and diastereoselective Lewis acid catalyzed Friedel–Crafts reaction of indole with cyclic allylic alcohols and intramolecular reductive Heck
Control of Stereoselectivity in Diverse Hapalindole Metabolites is Mediated by Cofactor‐Induced Combinatorial Pairing of Stig Cyclases
作者:Shasha Li、Sean A. Newmister、Andrew N. Lowell、Jiachen Zi、Callie R. Chappell、Fengan Yu、Robert M. Hohlman、Jimmy Orjala、Robert M. Williams、David H. Sherman
DOI:10.1002/anie.201913686
日期:2020.5.18
The stereospecific polycyclic core formation of hapalindoles and fischerindoles is controlled by the Stig cyclases through a three-step cascade involving Cope rearrangement, 6- exo -trig cyclization and a final electrophilic aromatic substitution. Here we report a comprehensive study of all currently annotated Stig cyclases, and reveal that these proteins can assemble into heteromeric complexes induced
Discovery of a Calcium-Dependent Enzymatic Cascade for the Selective Assembly of Hapalindole-Type Alkaloids: On the Biosynthetic Origin of Hapalindole U
作者:Qin Zhu、Xinyu Liu
DOI:10.1002/anie.201703932
日期:2017.7.24
to the discovery of an unprecedented calcium-dependent AmbU1-AmbU4 enzymatic complex for the selective formation of 4. This discovery refuted the intermediacy of 3 and bridged the missing links in the early-stage biosynthesis of ambiguines. This work further established the isomerocyclases involved in the biogenesis of hapalindole-type alkaloids as a new family of calcium-dependent enzymes, where the
New alkaloids called hapalindoles, which are antibacterial and antifungal agents, and methods of preparing these alkaloids by culturing the blue-green alga Hapalosiphon fontinalis ATCC 39694, are provided.