401792-87-8Relevant articles and documents
Practical total syntheses of acromelic acids A and B
Inai, Makoto,Ouchi, Hitoshi,Asahina, Aya,Asakawa, Tomohiro,Hamashima, Yoshitaka,Kan, Toshiyuki
, p. 723 - 732 (2016/07/19)
Practical total syntheses of acromelic acids A (1) and B (2), which were scarce natural products isolated from toxic mushroom by Shirahama and Matsumoto, were accomplished in 13 (36% total yield) and 17 steps (6.9% total yield), respectively, from 2,6-dichloropyridine (8). Beginning with regioselective transformation of symmetric 8 by either ortho-lithiation or bromination, nitroalkenes 15 and 16 were provided. Stereoselective construction of the vicinal stereocenters at the C-3, 4 positions of 1 and 2 was performed by a Ni-catalyzed asymmetric conjugate addition of α-ketoesters to the nitroalkenes. Construction of the pyrrolidine ring was accomplished in a single operation via a sequence consisting of reduction of the nitro group, intramolecular condensation with the ketone, and reduction of the resulting ketimine.
Nonproteinogenic amino acids: An efficient asymmetric synthesis of (S)-(-)-acromelobic acid and (S)-(-)-acromelobinic acid
Adamczyk, Maciej,Akireddy, Srinivasa Rao,Reddy, Rajarathnam E
, p. 6951 - 6963 (2007/10/03)
An efficient synthesis of (S)-(-)-acromelobic acid (1) and (S)-(-)-acromelobinic acid (2) is described via asymmetric hydrogenation protocol. Asymmetric hydrogenation of dehydroamino acid derivative 23 using (R,R)-[Rh(DIPAMP)(COD)]BF4 catalyst followed by removal of the protective groups afforded (S)-(-)-acromelobic acid (1) in >98% ee. The key intermediate 23 was prepared from citrazinic acid (8). The dehydroamino acid derivative 33 required for the synthesis of (S)-(-)-2 was prepared from 2,5-lutidine (27), which upon hydrogenation using (S,S)-[Rh(Et-DuPHOS)(COD)]BF4 catalyst afforded (S)-(+)-34 in 93% yield and >96% ee. Removal of protective groups in (S)-(+)-34 afforded (S)-(-)-acromelobinic acid (2) in good overall yield.
