Synthesis and application of bifunctional organic catalysts for direct amide condensation between carboxylic acids and amines

ORGN 652

Kenny Arnold, kenny.arnold@durham.ac.uk1, Bryan Davies2, and Andrew Whiting, andy.whiting@durham.ac.uk1. (1) Department of Chemistry, Durham University, Science Laboratories, South Road, Durham, DH1 3LE, United Kingdom, (2) Strategic Technologies, GlaxoSmithKline, Gunnels Wood Road, Stevenage, SG1 2NY, United Kingdom

The development of general synthetic routes to amino-boronic acid systems, and investigations into their use as potential bifunctional catalysts for a variety of transformations has been undertaken.  Three new derivatives of N,N-diisopropylbenzylamine-2-boronic acid 1a have been prepared by directed metallation-borylation methods and their activity assessed on the direct amide condensation.  Whilst the addition of an electron withdrawing group (1b and 2) does not substantially improve the reactivity of such systems, incorporation of an electron donating group (1c) results in considerably lower catalyst reactivity.  A Design of Experiments (DoE) study has been undertaken and the results used as a basis to improve isolated yields for more problematic substrates.