Asymmetric Garratt–Braverman Cyclization: A Route to Axially Chiral Aryl Naphthalene–Amino Acid Hybrids

We report the first example of a highly diastereoselective Garratt–Braverman cyclization leading to the synthesis of chiral aryl naphthalene–amino acid hybrids in excellent yields. The stereogenecity in the amino acid has induced high diastereoselectivity for the reaction. Computations based on density functional theory indicated a lower activation free energy barrier for the M isomer as compared to that for the P diastereomer (ΔΔG = 3.48 kcal/mol). Comparison of the recorded CD spectrum of the product with the calculated one also supported the preferential formation of the M diastereomer.