6 research outputs found
One-Pot Conversion of <i>N</i>‑Allyl-α-cyano Esters to α‑Allyl-α-cyano Lactams through a Hydrolysis/Ketene Formation/Cyclization/Claisen Rearrangement Sequence
An intramolecular ketene aza-Claisen
rearrangement is developed
for the first time to enable the stereoselective synthesis of α-ally-α-cyano-lactams
from <i>N</i>-allyl amino esters. This reaction also exhibits
outstanding chemoselectivity when an unsymmetrical bis-<i>N</i>-allyl group is present in the starting molecule. The usefulness
of this method is demonstrated by a short synthesis of optically active
bicyclolactam from l-proline
The Reaction of 2,3-Dimethylimidazole-1-sulfonyl Azide Triflate with 3‑Substituted Indoles: Reactivity and Scope
2,3-Dimethylimidazole-1-sulfonyl
azide triflate reacts with 3-substituted
indoles to deliver 2-iminoindolines, 2-aminoindoles, or 2-imino-3-aminoindolines
by using different conditions. This imidazolium sulfonyl azide shows
higher reactivity toward carbon nucleophile indoles than ordinary
alkyl/aryl sulfonyl azides
Stereoselective Construction of Bridged <i>trans</i>-aza-BicycloÂ[7/6,3/2,1]Âalkenyl Imines through Ring Expansion aza-Cope Rearrangement
A highly
stereoselective method for efficient synthesis of unprecedented
bridged bicycloÂ[7/6,3/2,1]Âalkenyl amidines is described
using cyclic <i>N</i>-allyl-aminoalkyne as a substrate.
A ketenimine formation/cyclization/aza-Cope rearrangement cascade
proceeds either with or without the aid of external DIPEA depending
on substrate basicity. Fused bicycloamidines are also obtained via
the same protocol using different <i>N</i>-allyl cyclic
aminoalkynes
One-Pot Protocol to Functionalized Benzopyrrolizidine Catalyzed Successively by Rh<sub>2</sub>(OAc)<sub>4</sub> and Cu(OTf)<sub>2</sub>: A Transition Metal–Lewis Acid Catalysis Relay
4-<i>N</i>-Allylarylpropylamino-1-sulfonyl
triazoles
are converted to structurally unique benzopyrrolizidinyl sulfonamides
in a one-pot operation. Intramolecular capture of rhodium carbene
with arylamino nitrogen gives rise to the formation of an ammonium
ylide immediate. A [2,3]- or [1,2]-rearrangement occurs to give a
2-allylpyrrolidinyl-2-carbimine intermediate which undergoes CuÂ(OTf)<sub>2</sub> catalyzed aza-Friedel–Crafts cyclization to finish
a highly functionalized tricyclic system decorated with a synthetically
difficult quaternary carbon center, a sulfonamide group, and an allyl
segment
Copper-Catalyzed Borylative Cyclization of Substituted <i>N</i>‑(2-Vinylaryl)benzaldimines
A <i>t-</i>BuOCu-initiated reaction sequence of styrene
borometalation and intramolecular imine addition has been achieved
using a CuÂ(OTf)<sub>2</sub>/dppf combination as catalyst. The product
of this reaction cascade is a useful 2,3-disubstituted indoline bearing
a versatile boryl moiety and is formed with sole <i>cis</i>-selectivity. To account for the observation of the exclusive formation
of <i>cis</i>-stereoisomers, a transition state featuring
copper–imine coordination is suggested. The application to
the synthesis of antioxidant tetrahydroindenoindoles is described
Rhodium-Catalyzed Chemo- and Regioselective Cross-Dimerization of Two Terminal Alkynes
Cross-dimerization of terminal arylacetylenes and terminal propargylic alcohols/amides has been achieved in the presence of a rhodium catalyst. This method features high chemo- and regioselectivities rendering convenient and atom economical access to functionalized enynes