Expanding the scope of the elpaN-type library: glucose-derived bis(pyridine-2-carboxamide) ligands (elpaN-Py) for molybdenum-catalyzed asymmetric allylic alkylations

The elpaN-Py family of ligands, which represents a subset of the elpaN-type library based on d-glucose, is described. The ligands are structural analogs of the privileged bis(pyridine-2-carboxamides) derived from trans-1,2-diaminocyclohexane, and differ for the type of substitution in the coordinating functions present in positions 1 and 2. Their ability to induce high enantioselectivity in asymmetric allylic alkylations promoted by molybdenum under microwave irradiation has been successfully demonstrated, starting from both a linear (ee up to 99%) and a branched substrate (ee up to 96%). The multifunctional nature of the sugar scaffold was exploited for the preparation of a polar ligand, through deprotection of the hydroxyl groups in positions 3, 4 and 6. In this version, it was possible to verify the performance in catalysis in alternative solvents, such as ionic liquids and water.

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