The twisted amide 2-quinuclidone: 60 years in the making.
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Amides↗
Biomedical subjects
Wesley J Moran
Publications and source records attributed to Wesley J Moran.
Rh-catalyzed enantioselective hydrogenation of vinyl boronates for the construction of secondary boronic esters.
[reaction: see text] Rh-catalyzed hydrogenation of prochiral vinyl boronates occurs in an enantioselective fashion in the presence of the chiral ligand Walphos 1. This transformation provides access to chiral secondary organoboronates that are not available from alkene hydroboration reactions. The chiral reaction products should be useful in organic synthesis, and preliminary experiments suggest that they may participate in one-pot amination and homologation reactions.
Boron Compounds↗
Development of a flexible approach to Nuphar alkaloids via two enantiospecific piperidine-forming reactions.
In this paper we describe the stereoselective synthesis of functionalized lactam 7 via two enantiospecific piperidine-forming techniques and its employment in a general synthetic approach to Nuphar alkaloids. Specifically, the formation of piperidine 18 by formal [3 + 3] cycloaddition and stepwise annelation processes is described; the latter technique was found to be significantly more efficient than the Pd-catalyzed TMM addition process. Finally, exploitation of the exocyclic alkene installed in the piperidine-forming reaction in the transformation of 18 to (-)-deoxynupharidine ((-)-2), (-)-castoramine ((-)-3), and (-)-nupharolutine ((-)-4) via intermediate lactam 7 is delineated.
Alkaloids↗
A concise asymmetric route to Nuphar alkaloids. A formal synthesis of (-)-deoxynupharidine.
[reaction: see text] A stereocontrolled route to Nuphar alkaloids is described that employs a formal [3 + 3] cycloaddition strategy to assemble the piperidine nucleus. The addition of Pd-TMM complexes to aziridine 10 was found to be sluggish; however, the addition of a functionalized allyl Grignard reagent followed by a Mitsunobu condensation reaction provided 11 in high yield. The employment of this route in the formal synthesis of (-)-deoxynupharidine 1 is described.
Alkaloids↗
Development of a [3+3] cycloaddition strategy toward functionalized piperidines.
This paper describes a novel route to functionalized piperidines via a formal [3+3] cycloaddition reaction of activated aziridines and palladium-trimethylenemethane (Pd-TMM) complexes. The cycloaddition reaction generally proceeds enantiospecifically with ring opening at the least hindered site of the aziridine. Therefore, readily available enantiomerically pure 2-substituted aziridines can be utilized to prepare enantiomerically pure 2-substituted piperidines in good to excellent yield. The N-substituent on the aziridine proved to be crucial to the success of this reaction with only 4-toluenesulfonyl (Ts) and 4-methoxybenzenesulfonyl (PMBS) aziridines permitting smooth cycloaddition to take place. Additionally, spirocyclic aziridines have been found to participate in the [3+3] cycloaddition reaction, whereas 2,3-disubstituted aziridines can be applied to provide fused bicyclic piperidines, albeit in low yield.
Aziridines↗