skip to main content


Title: Ag I ‐Catalyzed Reaction of Enol Diazoacetates and Imino Ethers: Synthesis of Highly Functionalized Pyrroles
Abstract

An unprecedented AgI‐catalyzed efficient method for the coupling of imino ethers and enol diazoacetates through a [3+2]‐cycloaddition/C−O bond cleavage/[1,5]‐proton transfer cascade process is reported. The general class of imino ethers that includes oxazolines, benzoxazoles and benzimidates are applicable substrates for these reactions that provide direct access to fully substituted pyrroles with uniformly high chemo‐ and regioselectivity. High variability in substitution at the pyrrole 2‐, 5‐ and N‐positions characterizes this methodology that also presents an entry point for further pyrrole diversification via facile modification of resulting N‐functional pyrroles.

 
more » « less
NSF-PAR ID:
10226912
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Angewandte Chemie
Volume:
133
Issue:
24
ISSN:
0044-8249
Page Range / eLocation ID:
p. 13506-13512
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    An unprecedented AgI‐catalyzed efficient method for the coupling of imino ethers and enol diazoacetates through a [3+2]‐cycloaddition/C−O bond cleavage/[1,5]‐proton transfer cascade process is reported. The general class of imino ethers that includes oxazolines, benzoxazoles and benzimidates are applicable substrates for these reactions that provide direct access to fully substituted pyrroles with uniformly high chemo‐ and regioselectivity. High variability in substitution at the pyrrole 2‐, 5‐ and N‐positions characterizes this methodology that also presents an entry point for further pyrrole diversification via facile modification of resulting N‐functional pyrroles.

     
    more » « less
  2. A facile metal‐free [2,3]‐sigmatropic rearrangement reaction of allyl sulfides viaN‐sulfilimine intermediates has been developed. Treatment of allyl sulfides with imino‐λ3‐iodanes in the presence of a catalytic amount of elemental iodine allowed the reaction to proceed under mild conditions and gave the correspondingN‐allylsulfenamide compounds in moderate to good yields. SeveralN‐allylsulfenamide structures have been confirmed by single‐crystal X‐ray crystallography. The reaction initially involves the sulfonylimino group transfer reaction between imino‐λ3‐iodane and the sulfur atom, resulting in the formation ofN‐sulfilimine species, followed by [2,3]‐sigmatropic rearrangement to form theN‐allylsulfenamide.

     
    more » « less
  3. Abstract

    We report that O‐selective arylation of 2‐ and 4‐pyridones with arylboronic acids is affected by a modular, bismacycle‐based system. The utility of this umpolung approach to pyridyl ethers, which is complementary to conventional methods based on SNAr or cross‐coupling, is demonstrated through the concise synthesis of Ki6783 and picolinafen, and the formal synthesis of cabozantib and golvatinib. Computational investigations reveal that arylation proceeds in a concerted fashion via a 5‐membered transition state. The kinetically‐controlled regioselectivity for O‐arylation—which is reversed relative to previous BiV‐mediated pyridone arylations—is attributed primarily to the geometric constraints imposed by the bismacyclic scaffold.

     
    more » « less
  4. Abstract

    We report that O‐selective arylation of 2‐ and 4‐pyridones with arylboronic acids is affected by a modular, bismacycle‐based system. The utility of this umpolung approach to pyridyl ethers, which is complementary to conventional methods based on SNAr or cross‐coupling, is demonstrated through the concise synthesis of Ki6783 and picolinafen, and the formal synthesis of cabozantib and golvatinib. Computational investigations reveal that arylation proceeds in a concerted fashion via a 5‐membered transition state. The kinetically‐controlled regioselectivity for O‐arylation—which is reversed relative to previous BiV‐mediated pyridone arylations—is attributed primarily to the geometric constraints imposed by the bismacyclic scaffold.

     
    more » « less
  5. Abstract We describe Pt(II)- and Fe(III)-catalyzed iminocarboxylations of oxime esters conjugated with 1,3-enyne and an ortho-alkynylarene moiety, followed by a spontaneous O→N acyl migration of the enol carboxylate intermediate to generate N-acyl pyrroles and isoindoles. The reaction scope for pyrrole synthesis is general, whereas the formation of isoindoles has a relatively narrow scope because of their instability. 
    more » « less