Stereoselective synthesis of 2-epi-jaspine B via base-catalyzed intramolecular oxy-Michael conjugate addition approach

2-epi-Jaspine B has been synthesized starting from (−)-diethyl tartrate in 12 simple steps and 26.6% overall yield. The key intermediate was obtained via stereoselective base-catalyzed intramolecular oxy-Michael conjugate addition followed by tandem hydrogenation/hydrogenolysis.

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(2R,3S,4S)-4-Amino-2-tetradecyltetrahydro-3-furanol TFA saltC20H38F3NO4[α]D25=+13.6 (c 1, EtOH)Chiral source: d-(−)-diethyl tartrateAbsolute configuration: (2R,3S,4S)

tert-Pentyl N-(3S,4S,5R)-4-(benzyloxy)-5-[(Z)-2-tetradecenyl]tetrahydro-3-furanylcarbamateC30H49NO4[α]D25=+6.8 (c 1, CHCl3)Chiral source: d-(−)-diethyl tartrateAbsolute configuration: (3S,4S,5R)

Ethyl 2-((2R,3S,4S)-3-(benzyloxy)-4-[(tert-pentyloxy)carbonyl]aminotetrahydro-2-furanyl)acetateC20H29NO6[α]D25=+11.5 (c 1, CHCl3)Chiral source: d-(−)-diethyl tartrateAbsolute configuration: (2R,3S,4S)

tert-Butyl (4S)-4-[(1R,2E)-1-(benzyloxy)-4-ethoxy-4-oxo-2-butenyl]-2,2-dimethyl-1,3-oxazolane-3-carboxylateC23H33NO6[α]D25=-22.2 (c 1, CHCl3)Chiral source: d-(−)-diethyl tartrateAbsolute configuration: (4S,1R,2E)

tert-Butyl (4S)-4-[(1S)-1-benzyloxyethyl]-2,2 dimethyl-1,3-oxazolane-3-carbamateC19H29NO5[α]D25=-50.0 (c 1, CHCl3)Chiral source: d-(−)-diethyl tartrateAbsolute configuration: (1R,4S)

1-[(1R,2S)-2-(Benzyloxy)-3-ethoxy-1-(ethoxycarbonyl)-3-oxopropyl]-1,2-triazadien-2-iumC15H19N3O5[α]D25=+5.5 (c 1, CHCl3)Chiral source: d-(−)-diethyl tartrateAbsolute configuration: (1R,2S)

1-[(1R,2S)-3-Ethoxy-1-(ethoxycarbonyl)-2-hydroxy-3-oxopropyl]-1,2-triazadien-2-iumC8H13N3O5[α]D25=-30.5 (c 1, CHCl3)Chiral source: d-(−)-diethyl tartrateAbsolute configuration: (1R,2S)

tert-butyl N-[(1S,2S)-2-(benzyloxy)-3-hydroxy-1-(hydroxymethyl)propyl]carbamateC16H25NO5[α]D25=-45.4 (c 1, CHCl3)Chiral source =d-(−)-Diethyl tartrateAbsolute configuration = (1S,2S)