Asymmetric synthesis of (S)-(-)-acromelobinic acid

A total synthesis of (S)-(-)-acromelobinic acid 2, which was isolated from elitocybe acromelalga, was achieved via an asymmetric hydrogenation protoco l. Dehydroamino acid derivative 12 was prepared from 2.5-lutidine 5 and sub jected to asymmetric hydrogenation using (S,S)-[Rh(Et-DuPHOS)(COD)]BF4 to g ive the (S)-(+)-pyridylalanine derivative 13 in 93% yield and > 96% e.e. Re moval of the protecting groups in (S)-(+)-13 afforded (S)-(-)-acromelobinic acid 2. (C) 2001 Elsevier Science Ltd. All rights reserved.