Tuning the Chemoselectivity of the Metathesis Reactions of N‐Substituted 2‐Azabicyclo[2.2.1]hept‐5‐en‐3‐one

Abstract

Keywords: Metathesis / Pyrrolidinone / Pyrrolizidinone / Hoveyda-Grubbs catalyst / Aza compounds / Bicyclic compounds By using the second-generation Hoveyda-Grubbs precatalyst, the metathesis transformations of N-substituted 2-azabicyclo[2.2.1]hept-5-en-3-one derivatives have been explored. In the absence of any external alkene (cross-metathesis partner), substituted pyrrolizidin-3-one derivatives were obtained by ring-opening metathesis/ring-closing metathesis tandem reactions. In the presence of an external alkene, N-

Ring‐Rearrangement Metathesis of Nitroso Diels–Alder Cycloadducts

“…If an external alkene is not present to intercept the ROM intermediate it is evident that the rate of polymerization is superior to the rate of the RCM (Table 3, entry 1). This is in contrast with the Ru‐catalyzed reaction of N ‐acryloyl‐2‐aza‐bicyclo[2.2.1]hept‐5‐en‐3‐ones in the absence of external alkenes or ethylene, which led cleanly to the desired rearranged bicycles, as described by Aljarilla and Plumet 4e. It was previously postulated that coordination of the Ru–carbene by the exocyclic carbonyl moiety would stabilize the intermediate VI (Scheme ) and, thus, slow the rate of RCM.…”

“…In this RRM process different reaction pathways may be operative, dependent on various factors (Scheme ) 4e…”

2-Azabicyclo[2.2.1]hept-5-en-3-one: Chemical Profile of a Versatile Synthetic Building Block and its Impact on the Development of Therapeutics

“…Both, first and second generation Grubbs’ catalysts were used for mediating the reactions. Furthermore, Arjona and Plumet independently revealed their studies focused on preparing 3,5-disubstituted pyrrolidines and prolines, and the preparation of functionalized tetrahydro-6 H -pyrrolizidin-3-ones, respectively, from the domino metathesis of Vince lactam. Their efforts established the substrate scope of various olefins as prospective reactants.…”