An efficient and practical entry to 2-amido-dienes and 3-amido-trienes from allenamides through stereoselective 1,3-hydrogen shifts

Abstract

SummaryPreparations of de novo acyclic 2-amido-dienes and 3-amido-trienes through 1,3-hydrogen shifts from allenamides are described. These 1,3-hydrogen shifts could be achieved thermally or they could be promoted by the use of Brønsted acids. Under either condition, these processes are highly regioselective in favour of the α-position, and highly stereoselective in favour of the E-configuration. In addition, 6π-electron electrocyclic ring-closure could be carried out with 3-amido-trienes to afford cyclic 2-amido-dienes, and such electrocyclic ring-closure could be rendered in tandem with the 1,3-hydrogen shift.

Recent progress in transition-metal-free functionalization of allenamides

“…Hsung et al 29 subsequently expanded the substrate scope of the 1,3-H shi reaction for the preparation of 3-amido-trienes 83. Such 1,3-hydrogen shis could be achieved thermally or via Brønsted acid promotion (Scheme 22).…”

Copper-Catalyzed Skeletal Rearrangements ofO-Propargylic Oximes via Cleavage of a Carbon-Oxygen Bond

“…Moreover, amidodienes have recently gained considerable interest as unique, efficient reactants in organocatalytic reactions. [] Therefore, our methodology would be useful in affording functionalized amidodienes efficiently under mild reaction conditions.…”

Facile Synthesis of 3-Amido-Dienynes via a Tandem α-Propargylation–Isomerization of Chiral Allenamides and their Applications in Diels–Alder Cycloadditions

“…1,2 Furthermore, chiral 3-amidotrienes such as 2 could be prepared by the reactions starting from α-allyl-allenamides 1 (path a, scheme 1), which could be facilely converted to cyclic 2-amidodienes 4 and further applied in various different transformations. 1, 3 …”