Rosa Griera

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

A practical synthetic route to enantiopure 5-substituted cis-decahydroquinolines 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.

Biomimetic construction of the hydroquinoline ring system. Diastereodivergent enantioselective synthesis of 2,5-disubstituted cis-decahydroquinolines.

The straightforward enantioselective construction of the hydroquinoline ring system from 1,5-polycarbonyl derivatives, using (R)-phenyglycinol as a chiral latent form of ammonia, is reported. The process mimics the key steps believed to occur in nature in the biosynthesis of amphibian decahydroquinoline alkaloids. Diastereodivergent routes to enantiopure cis-2,5-disubstituted decahydroquinolines, including the alkaloid pumiliotoxin C (cis-195A), are developed.

Synthesis and pharmacological evaluation of new cysLT1 receptor antagonists

Summary This paper describes the synthesis and pharmacological evaluation of three series of compounds 4a–b , 13a–k and 19 , structurally related to the known potent cysLT 1 receptor antagonists RG-12553, ICI-204219 and ONO-1078 , respectively. The common structural feature of these new series is the presence of a 4-quinolone nucleus acting as a template for substitution of the aromatic nucleus present in the prototype antagonists. We describe the evolution of these series leading to antagonists with potency at nanomolar concentrations in vitro.

Stereoselective Syntheses of the Antihistaminic Drug Olopatadine and Its E-Isomer

Practical stereoselective synthetic routes to the antihistaminic drug olopatadine and its E-isomer have been developed, the key steps being a trans stereoselective Wittig olefination using a nonstabilized phosphorus ylide and a stereoselective Heck cyclization. The stereoselectivity of the Wittig reaction depends on both the phosphonium salt anion and the cation present in the base used to generate the ylide.

Enantio‐ and Diastereoconvergent Cyclocondensation Reactions: Synthesis of Enantiopure cis‐Decahydroquinolines

Up to four stereocenters with a well-defined configuration are generated in a single synthetic step by the cyclocondensation of (R)-phenylglycinol or (1S,2R)-1-amino-2-indanol with stereoisomeric mixtures (racemates, meso forms, diastereoisomers) of cyclohexanone-based δ-keto-acid and δ-keto-diacid derivatives in enantio- and diastereoconvergent processes that involve dynamic kinetic resolution and/or desymmetrization of enantiotopic groups. A detailed analysis of the stereochemical outcome of this process is presented. This method provides easy access to enantiopure 8- and 6,8-substituted cis-decahydroquinolines, including alkaloids of the myrioxazine family.

Stereoselective synthesis 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.

Access to Enantiopure 5-, 7-, and 5,7-Substituted cis-Decahydroquinolines: Enantioselective Synthesis of (-)-Cermizine B

Stereoconvergent cyclocondensation reactions of (R)- or (S)-phenylglycinol with appropriately substituted cyclohexanone-based δ-keto esters are the key steps of short synthetic routes to enantiopure 5-, 7-, and 5,7-substituted cis-decahydroquinolines. The factors governing the stereoselectivity of the cyclocondensation are discussed. The potential of the methodology is illustrated by a protecting-group-free synthesis of the phlegmarine-type Lycopodium alkaloid (-)-cermizine B.

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.

Nucleophilic Substitution of 7-Chloro-1-Methyl-4-Quinolone

Abstract Substitution of 7-chloro-1-methyl-4-quinolone with O- and N- nucleophiles is described.