Total Synthesis of a PPAP, Nemorosonol, Using a Tandem Michael Addition–Intramolecular Aldol Reaction

Abstract

A strategy for constructing a tricyclo­[4.3.1.03,7]­decane skeleton, which is common to many polycyclic polyprenylated acylphloroglucinols, has been established. The key step was a tandem Michael addition–intramolecular aldol reaction with 3-ethoxy-1-phenyl-2-proyn-1-one, which affords a tricyclo­[4.3.1.03,7]­decane skeleton having a benzoyl group at the C8 position and an appropriate oxygen functional group at the C9 position. This synthetic strategy led to the total synthesis of nemorosonol, which was accomplished in 12 steps from 2-methyl-2-cyclopenten-1-one.

Iron-Catalyzed Coupling of Alkenes and Enones: Sakurai–Michael-type Conjugate Addition of Catalytic Allyliron Nucleophiles

“…The Sakurai–Michael reaction has been applied as a key step in the synthesis of several biologically relevant molecules, including (−)-xialenon A, (±)-hirsutene and (±)-capnellene, (−)-acutumine and (−)-dechloroacutumine, ent -callilongisin B, and 3- epi -hypatulin B . It has also been used as a tool for the construction of useful early building blocks for natural product synthesis . In this Communication, we report the development of an iron-catalyzed coupling of alkenes and enones that realizes this novel C–C bond-forming strategy, delivering δ,ε-unsaturated ketones through the generation of catalytic allyliron intermediates that undergo subsequent 1,4-addition.…”

Hyperpatone A, a polycyclic polyprenylated acylphloroglucinol with a rare 8/6/5/6/5 pentacyclic skeleton from Hypericum patulum

“…Finally, the novel peroxy bridge of compound 1 could be obtained after the nucleophilic reaction, oxidation, and dehydration reaction of vii . 32…”

“…Finally, the novel peroxy bridge of compound 1 could be obtained after the nucleophilic reaction, oxidation, and dehydration reaction of vii. 32 The isolates were screened for cytotoxicity against the HEL (human erythroleukemia) cell line by an MTT method. 19 Compounds 1 and 2 exhibited moderate cytotoxicity against the HEL cancer cell line, with IC 50 values of 19.23 μM and 10.2 μM, respectively.…”