15NRORC: An Azine Labeling Protocol.

A practical method for the synthesis of 15N-labeled azines with a high degree of isotopic enrichment is described. Activation of azine heterocycles with an electron-deficient arene allows for the facile substitution of the nitrogen atom with a specifically designed 15N-labeled reagent that undergoes a canonical ANRORC-type mechanism. A wide range of azines can be converted to their corresponding 15N isotopologs using this method, and it also allows for dearomative access to reduced heterocyclic congeners. A short dearomative formal synthesis of 15N-solifenacin is accomplished as well to demonstrate a practical application of this method for generating labeled pharmaceuticals.

Dearomative Access to (-)-Thebaine and Derivatives.

A synthesis of the natural product thebaine is reported in eight steps from commercially available starting materials, hinging on the dearomatization and coupling of simple aromatic starting materials. This provides divergent access to two unnatural opioid derivatives and is aimed at the long-term development of synthetic opioid analogs of the "wonderdrug" Naloxone. Additionally, a formal enantioselective synthesis of all reported targets is disclosed that leverages a catalytic asymmetric dearomatization via anion-pairing catalysis.

A predictive model for additions to N-alkyl pyridiniums.

Disclosed in this communication is a thorough study on the dearomative addition of organomagnesium nucleophiles to N-alkyl pyridinium electrophiles. The regiochemical outcomes have observable and predictable trends associated with the substituent patterns on the pyridinium electrophile. Often, the substituent effects can be either additive, giving high selectivities, or ablative, giving competing outcomes. Additionally, the nature of the organometallic nucleophilic component was also investigated for its role in the regioselective outcome. The effects of either reactive component are important to both the overall reactivity and site of nucleophilic addition. The utility of these observed trends is demonstrated in a concise, dearomative synthesis of a tricyclic compound shown to have insecticidal activity.