A General Synthetic Route to Enantiopure 5-Substituted cis-Decahydroquinolines

A practical synthetic route to enantiopure 5-substituted cisdecahydroquinolines has been developed, the key steps being a stereoselective cyclocondensation of 2-substituted 6-oxocyclohexenepropionates 2 with (R)-phenylglycinol, the stereoselective hydrogenation of the resulting unsaturated tricyclic lactams, and the stereoselective reductive cleavage of the oxazolidine ring

Stereoselectivesynthesis of (-)-lepadins A-C

A concise synthesis of the marine alkaloids ()-lepadins A-C from a phenylglycinol-derived tricyclic lactam is reported. Key steps from the stereochemical standpoint involve stereoselective cyclocondensation, double bond hydrogenation, oxazolidine opening, hydroboration- oxidation, and Horner-Wadsworth-Emmons reactions

Enantioselective synthesis of lepadins A D from a phenylglycinol-derived hydroquinolone lactam

The marine alkaloids (-)-lepadins A-C and (+)-lepadin D, belonging to two diastereoisomeric series, were synthesized from an (R)-phenylglycinol-derived tricyclic lactam via a common cis-decahydroquinoline intermediate. Crucial aspects of the synthesis are the stereochemical control in the assembly of the cis-decahydroquinoline platform, in the introduction of the C2 methyl and C3 hydroxy substituents, and in the generation of the C5 stereocenter

Enantioselective formal synthesis of (+)-madangamine A

An enantioselective formal synthesis of the marine alkaloid madangamine A using phenylglycinol-derived lactam 1 as the starting enantiomeric scaffold is reported. The synthesis involves the construction of the C-9 substituted diazatricyclic ABC core and the final closure of D and E rings from the polyunsaturated skipped intermediate 19

Total Synthesis of (+)-Madangamine D

Madangamines are a group of bioactive marine sponge alkaloids, embodying an unprecedented diazapentacyclic skeletal type. The enantioselective total synthesis of madangamine D has been accomplished, and represents the first total synthesis of an alkaloid of the madangamine group. It involves the stereoselective construction of the diazatricyclic ABC core using a phenylglycinol-derived lactam as the starting enantiomeric scaffold and the subsequent assembly of the peripheral macrocyclic rings. The synthesis provides, for the first time, a pure sample of madangamine D and confirms the absolute configuration of this alkaloid family

Synthesis of fluvirucins and their aglycons, the fluvirucinins

Fluvirucins are bioactive macrolactam glycosides isolated from actinomycetes. This review gives an overview of this family of natural products, covering isolation, biological activities, biosynthesis, and total synthesis. The synthesis of fluvirucins and their aglycons, the fluvirucinins, is presented, paying special attention to the synthetic strategy and stereochemical aspects. 1 Introduction 2 Isolation, Biological Activity, and Biosynthesis 3 Synthetic Approaches 3.1 Closure of the 14-Membered Ring by Ring-Closing Metathesis 3.2 Closure of the 14-Membered Ring by Macrolactamization 3.3 Construction of the 14-Membered Ring by Aza-Claisen Ring Expansion 4 Conclusio

Access to enantiopure 4-substituted 1,5-aminoalcohols from phenylglycinol-derived δ-lactams: synthesis of Haliclona alkaloiods

LiNH2BH3-promoted reductive opening of 8-substituted phenylglycinol-derived oxazolopiperidone lactams leads to enantiopure 4-substituted-5-aminopentanols, which are used as starting building blocks in the synthesis of the Haliclona alkaloids haliclorensin C, haliclorensin, and halitulin (formal). The starting lactams are easily accessible by a cyclocondensation reaction of (R)-phenylglycinol with racemic γ-subtituted δ-oxoesters, in a process that involves a dynamic kinetic resolution

First Enantioselective Synthesis of Tetracyclic Intermediates en route to Madangamine D

The enantioselective synthesis of advanced tetracyclic precursors of madangamine D, bearing rings ABCD of this alkaloid, is reported. The saturated 14-membered ring is assembled from functionalized diazatricyclic intermediates 10 following either ring-closing metathesis or macrolactamization strategies

Enantioselective Total Synthesis of (+)-Gephyrotoxin 287C

A synthesis of (+)-gephyrotoxin 287C using, (S)-phenylglycinol-derived tricyclic lactam 7 as the starting enantiomeric scaffold is reported. From the stereochemical standpoint, the key steps are the generation of the DHQ C-5 stereocenter by hydrogenation of the C-C double bond, removal of the chiral inductor to give a cis-DHQ introduction of the DHQ C-2 substituent, completion of the (Z)-enyne moiety, and generation of the C-1 stereocenter during closure of the pyrrolidine ring

A practical synthetic route to enantiopure 6-substituted cis-decahydroquinolines

Starting from 4-substituted cyclohexanones, a practical synthetic route to enantiopure 6-substituted cis-decahydroquinolines has been developed, the key steps being a stereoselective cyclocondensation of an unsaturated δ-keto ester derivative with (R)-phenylglycinol and the stereoselective hydrogenation of the resulting tricyclic oxazoloquinolone lactams