Syntheses of enantioenriched homoallylic hydroxylamines and ß-lactams using sugar template as the chiral auxiliary.

87 p.The extensive occurrence of nitrogenated compounds in the nature and the promising outlook of synthesizing enantiomerically pure compounds in asymmetric reactions, the stereoselective additions to C=N bonds are now considered salient and fundamental reactions.The C=N functionalities are possible to determine the final products to be either amines (from imines and iminium salts) or hydroxylamines (from nitrones and oximes), which could later be transformed into useful building blocks like amino alcohols, amino acids and nitrogenated heterocycles such as isoxazolidine. A variety of nitrogen containing functional groups can be prepared by introducing the allyl moiety such as Grignard reagent or stannane reagent. The diastereoselective allylations can be performed in the presence of either a chiral lewis acid or a chiral auxiliary group. The discoveries of chiral Lewis acid systems and its applications are widely demonstrated in many papers; however, a very few examples of diastereoselective allylations are performed via chiral auxiliary group have been reported so far. Therefore, the development of allylation of nitrones using sugar template as a chiral auxiliary is highly desirable.​Master of Scienc

l-Proline-derived ligands to mimic the ‘2-His-1-carboxylate’ triad of the non-haem iron oxidase active site

Non-haem iron(II) oxidases (NHIOs) catalyse a variety of oxidative transformations in biology. The iron-binding environment of the NHIO active site typically incorporates a ‘2-His-1-carboxylate’ facial triad of amino acid side-chains, a motif that has emerged as a defining feature of the enzyme family. Towards the goal of biomimetic, iron-mediated C–H activation we have synthesized a series of peptidomimetic ligands from l-proline. By coupling l-proline to 2,6-bis(bromomethyl)pyridine, 2-(bromomethyl)-6-((tert-butyldimethylsilyloxy)methyl)pyridine and picolinic acid, we have generated several new ligand architectures designed to complex with iron(II) and mimic the NHIO active site. The resulting iron complexes promote modest levels of alkene dihydroxylation and allylic oxidation using hydrogen peroxide as oxidant