Scalable methodology for the catalytic, asymmetric alpha-bromination of acid chlorides.

نویسندگان

  • Cajetan Dogo-Isonagie
  • Tefsit Bekele
  • Stefan France
  • Jamison Wolfer
  • Anthony Weatherwax
  • Andrew E Taggi
  • Thomas Lectka
چکیده

The optimization of a practical, catalytic, asymmetric process for the alpha-bromination of acid chlorides to produce synthetically versatile, optically active alpha-bromoesters is reported. A range of products is produced in high enantioselectivity and moderate to good chemical yields with retention of both upon scale-up. The reactions herein are catalyzed by cinchona alkaloid derivatives, with the best performance achieved by the use of a proline cinchona alkaloid conjugate designed in a de novo fashion.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Reactive ketenes through a carbonate/amine shuttle deprotonation strategy: catalytic, enantioselective alpha-bromination of acid chlorides.

[reaction: see text] We have developed an efficient methodology for the generation of ketenes by employing a catalytic shuttle base and potassium carbonate as a stoichiometric base. We have applied this technology to the catalytic, asymmetric alpha-bromination of acid chlorides.

متن کامل

Generation of ketenes from acid chlorides using NaH/crown ether shuttle-deprotonation for use in asymmetric catalysis.

[reaction: see text] We describe methodology for the in situ generation of reactive monosubstituted ketenes from acid chlorides through a shuttle deprotonation process using NaH as an inexpensive stoichiometric base and a crown ether cocatalyst. We have successfully applied this new procedure to the catalytic, asymmetric synthesis of beta-lactams and alpha-haloesters.

متن کامل

A catalyst that plays multiple roles: asymmetric synthesis of beta-substituted aspartic acid derivatives through a four-stage, one-pot procedure.

We report a new method for the catalytic, asymmetric synthesis of beta-substituted aspartic acid derivatives in which the nucleophilic catalyst serves up to four discrete roles in a one-pot procedure: catalytic dehydrohalogenation of acid chlorides to form ketenes; catalytic dehydrohalogenation of alpha-chloroamines to form the corresponding imines; catalyzed [2 + 2]-cycloaddition to produce in...

متن کامل

Liquid phase bromination of phenols over silicotungstic acid immobilized on nickel oxide nanoparticles

Heteropoly acid promoted nanoparticle of nickel oxide samples were prepared by sol-gel method using heteropoly acids. Prepared composite was characterized by XRD, FT-IR and ICP technique. In this work, we have reported bromination of phenol, its derivatives and some aromatic compounds. The liquid phase bromination of phenol was Performed using heteropoly acids immobilized nanoparticle of nickel...

متن کامل

Catalytic, asymmetric alpha-fluorination of acid chlorides: dual metal-ketene enolate activation.

In this Communication, we disclose a catalytic, highly enantioselective (up to >99% ee) alpha-fluorination of acid chlorides to produce a variety of optically active carboxylic acid derivatives from readily accessible and commercially available starting materials. The reaction depends on dually activated ketene enolates generated from two discrete catalysts--a chiral nucleophile and an achiral ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • The Journal of organic chemistry

دوره 71 23  شماره 

صفحات  -

تاریخ انتشار 2006