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.