Ortho esters, 3-keto synthesis

On the other hand, the Gong group reported the enantioselective [l,5]-hydride transfer/cyclization reaction between ortho tertiary amine substituted aromatic keto esters 33 and aromatic amines 34 catalyzed by chiral bisphosphoric acid (1 ,1 )-C8, developed in their own group (Scheme 4.16). In this reaction, the in situ formed a-imino esters 36 act as the hydride acceptors, allowing the efficient synthesis of cyclic aminals 35 in high stereoselectivity (up to 14 1 dr, 90% ee). 

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