While aryl pyrrolidinoamido-thioureas derived from α-amino acids are effective catalysts in a number of asymmetric transformations, they exist as mixtures of slowly interconverting amide rotamers. Herein, the compromising role of amide bond isomerism is analyzed experimentally and computationally. A modified catalyst structure that exists almost exclusively as a single amide rotamer is introduced. This modification is shown to result in improved reactivity and enantioselectivity by minimizing competing reaction pathways.
While aryl pyrrolidinoamido-thioureas derived from α-amino acids are effective catalysts in a number of asymmetric transformations, they exist as mixtures of slowly interconverting n class="Chemical">amide rotamers. Herein, the compromising role of amide bond isomerism is analyzed experimentally and computationally. A modified catalyst structure that exists almost exclusively as a single amide rotamer is introduced. This modification is shown to result in improved reactivity and enantioselectivity by minimizing competing reaction pathways.
Authors: C Rose Kennedy; Dan Lehnherr; Naomi S Rajapaksa; David D Ford; Yongho Park; Eric N Jacobsen Journal: J Am Chem Soc Date: 2016-10-11 Impact factor: 15.419