A short synthesis of (+)-(S)-kurasoin B

A short efficient enantioselective synthesis leading directly to (+)-(S)-kurasoin B has been achieved in 5 steps and 25% overall yield from (2E)-ethyl-4-phenylbut-2-enoate using Sharpless asymmetric dihydroxylation and CH3NO2-assisted, or Yb(OTf)3-catalyzed, regioselective C-3 coupling of indole as the key steps.

An efficient short enantioselective synthesis leading directly to (+)-(S)-kurasoin B has been achieved in 5 steps and 25% overall yield from (2E)-ethyl-4-phenylbut-2-enoate using Sharpless asymmetric dihydroxylation and CH3NO2-assisted or Yb(OTf)3-catalyzed regioselective C-3 coupling of indole as the key steps.Figure optionsDownload as PowerPoint slide

(+)-(2S,3S)-1,2-Epoxy-4-phenylbutan-3-olC10H12O2Ee = 95%[α]D20=+6.42 (c 1.8, CHCl3)Source of chirality: asymmetric dihydroxylationAbsolute configuration: (2S,3S)

(−)-(2S)-1,2-Epoxy-4-phenylbutan-3-oneC10H10O2Ee = 95%[α]D20=-36.4 (c 1.5, CHCl3)Source of chirality: enantiopure reactantAbsolute configuration: (2S)

(+)-(S)-3-Hydroxy-4-(1H-indol-3-yl)-1-phenylbutan-2-oneC18H17NO2Ee = 95%[α]D20=+30.7 (c 0.15, CHCl3)Source of chirality: enantiopure reactantAbsolute configuration: (3S)