Amino-alcohol cyclization: selective synthesis of lactams and cyclic amines from amino-alcohols

Abstract

By employing an amination catalyst, previously used in the direct synthesis of amines from alcohol with ammonia, n-amino-alcohols could be selectively cyclized to either the amide or the amine. By the addition of water, the amine could be produced as the major product whereas adding a sacrificial ketone as a hydrogen acceptor resulted in the amide as the major product. Without an additive a mixture of both the amine and the amide was observed. N-substituted amino-alcohols solely gave cyclic amines under these conditions. From 2-(n-alkanol) anilines the cyclic amines were produced, where the n-propanol derivative selectively formed quinoline as the major product.Scheme 1 "Hydrogen Shuttling" in the intramolecular amino-alcohol cyclization.Scheme 2 A general reaction scheme for amino-alcohol cyclization.Catal. Sci. Technol. This journal is

Transition‐Metal‐Catalyzed Hydrogen‐Transfer Annulations: Access to Heterocyclic Scaffolds

“…Benzo-fused lactams,s uch as oxindoles,d ihydroquinolinones,a nd tetrahydrobenzazepinones are found in many natural products and drug candidates.Eco-benign and atomeconomical methods for the synthesis of such heterocyclic compounds are highly desirable.F ujita and co-workers reported aC p*-based rhodium complex in acetone as as elective catalyst for the synthesis of benzo-fused five-, six-, and seven-membered lactams (27), through ad ehydrogenative amide formation reaction [Eq. (10)].…”

“…[42] Hydrogen-transfer CÀCbond-forming reactions of vicinal diols with methyl acrylate,u sing the ruthenium(0) complex [Ru 3 (CO) 12 ]a nd dppp,w ere reported for the construction of lactones and spirolactones from acyclic and cyclic diols, respectively.Diversely substituted cyclic diols were converted into spirolactones in good to excellent yields [Eq. (27)]. T he mechanistic pathway for the formation of the lactone through CÀCc oupling and subsequent lactonization is shown in Scheme 13.…”

Übergangsmetallkatalysierte Wasserstofftransferanellierungen: Zugang zu heterocyclischen Gerüsten

“…Dieses Ergebnis könnte darauf zurückzuführen sein, dass Wasser oder Phenol als schwache Säure wirken und so die Dehydratisierung eines cyclischen Halbaminals zu einem Imin vereinfachen. Bei Zusatz von Propiophenon als Wasserstoffakzeptor wurde die selektiv das Amid gebildet 27 …”

Ruthenium-Catalyzed Amide-Bond Formation

“…Ruthenium complexes, and especially NHC-compounds, have been the most widely studied [94], albeit highly efficient processes promoted by rhodium or silver have also been described [112,113]. In regard to ruthenium, both in-situ-generated catalytic systems (Table 1) [114][115][116][117][118][119][120][121][122][123] as well as well-defined catalysts 38-44 ( Figure 10) [124][125][126][127][128][129][130][131] have been reported. In most of the cases, high metal loadings (usually 5 mol%) and an excess of a strong base (10-40 mol% of NaH or KO-t-Bu) were required to achieve satisfactory yields in the amides.…”