Saotome C, Ono M, Akita H
School of Pharmaceutical Sciences, Toho University, Funabashi, Chiba, Japan.
Chem Pharm Bull (Tokyo). 2001 Jul;49(7):849-53. doi: 10.1248/cpb.49.849.
A reaction of methyl (4R,5R)-4,5-epoxy-2(E)-hexenoate 1 with N-benzylmethylamine gave a diastereomerically pure methyl (4R,5R)-4,5-epoxy-(3S)-N-benzylmethylamino hexanoate 6 and methyl (4S,5R)-4-N-benzyl-methylamino-5-hydroxy-2(E)-hexenoate 7. The former was chemoenzymatically converted to (-)-osmundalactone 11, which is an aglycone of osmundalin. On the other hand, the directly conjugated addition of dimethylamine to methyl (4S,5S)-4,5-epoxy-2(E)-hexenoate 1 followed by treatment with MeOH at 40 degrees C exclusively provided methyl (4R,5S)-4-dimethylamino-5-hydroxy-2(E)-hexenoate 16, which was converted into L-(-)-forosamine 18.
