A convergent approach for the total synthesis of the α-glucosidase inhibitor (−)-panaxjapyne-C

The stereoselective total synthesis of (−)-panaxjapyne-C was accomplished in a convergent fashion. The synthesis utilizes the readily available enantiomers l-(+)-diethyltartrate and d-(−)-diethyltartrate and involves a Cadiot–Chodkiewicz coupling reaction, and an Ohira–Bestmann reaction as the key steps.

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(((4S,5S)-5-((Z)-6-(Benzyloxy)hex-1-en-1-yl)-2,2-dimethyl-1,3-dioxolan-4-yl)methoxy)(tert-butyl)diphenylsilaneC35H46O4Si[α]D25=+12.7 (c 0.6, CHCl3)Source of chirality: (+)-DiethyltartrateAbsolute configuration: (4S,5S-5Z)

tert-Butyl(((4S,5S)-5-(hept-6-en-1-yl)-2,2-dimethyl-1,3-dioxolan-4-yl)methoxy)diphenylsilaneC29H42O3Si[α]D25=-9.85 (c 5.0, CHCl3)Source of chirality: (+)-DiethyltartrateAbsolute configuration: (4S,5S)

6-((4S,5S)-5-(((tert-Butyldiphenylsilyl)oxy)methyl)-2,2-dimethyl-1,3-dioxolan-4-yl)hexan-1-olC28H42O4Si[α]D25=-4.2 (c 1.0, CHCl3)Source of chirality: (+)-DiethyltartrateAbsolute configuration: (4S,5S)

((4S,5S)-5-(Hept-6-en-1-yl)-2,2-dimethyl-1,3-dioxolan-4-yl)methanolC13H24O3[α]D25=-22.0 (c 2.7, CHCl3)Source of chirality: (+)-DiethyltartrateAbsolute configuration: (4S,5S)

(3-((4S,5S)-5-(Hept-6-en-1-yl)-2,2-dimethyl-1,3-dioxolan-4-yl)prop-1-yn-1-yl)trimethylsilaneC18H32O2Si[α]D25=-1.9 (c 1.5, CHCl3)Source of chirality: (+)-DiethyltartrateAbsolute configuration: (4S,5S)

(4S,5S)-4-(3-Bromoprop-2-yn-1-yl)-5-(hept-6-en-1-yl)-2,2-dimethyl-1,3-dioxolaneC15H23BrO2[α]D25=-9.1 (c 1.0, CHCl3)Source of chirality: (+)-DiethyltartrateAbsolute configuration: (4S,5S)

tert-Butyl(((4R,5S)-5-(iodomethyl)-2,2-dimethyl-1,3-dioxolan-4-yl)methoxy)diphenylsilaneC23H31IO3Si[α]D25=+6.2 (c 5.0, CHCl3)Source of chirality: (−)-DiethyltartrateAbsolute configuration: (4R,5S)

(S)-1-((tert-Butyldiphenylsilyl)oxy)but-3-en-2-olC20H26O2Si[α]D25=-4.6 (c 3.2, CHCl3)Source of chirality: (−)-DiethyltartrateAbsolute configuration: (2S)

(S)-1-((tert-Butyldiphenylsilyl)oxy)butan-2-olC20H28O2Si[α]D25=+4.2 (c 2.2, CHCl3)Source of chirality: (−)-DiethyltartrateAbsolute configuration: (2S)

(S)-Butane-1,2-diolC4H10O2[α]D25=+2.5 (c 1.0, CHCl3)Source of chirality: (−)-DiethyltartrateAbsolute configuration: (2S)

(S)-2-((4-Methoxybenzyl)oxy)butan-1-olC12H18O3[α]D25=+6.4 (c 1.5, CHCl3)Source of chirality: (−)-DiethyltartrateAbsolute configuration: (2S)

(S)-1-Methoxy-4-((pent-1-yn-3-yloxy)methyl)benzeneC13H16O2[α]D25=-108.3 (c 1.2, CHCl3)Source of chirality: (−)-DiethyltartrateAbsolute configuration: (3S)

(4S,5S)-4-(Hept-6-en-1-yl)-5-((S)-6-((4-methoxybenzyl)oxy)octa-2,4-diyn-1-yl)-2,2-dimethyl-1,3-dioxolaneC28H38O4[α]D25=-154.5 (c 1.5, CHCl3)Source of chirality: (−)-Diethyltartrate, (+)-DiethyltartrateAbsolute configuration: (4S,5S)-5-(S)

(3S,9S,10S)-Heptadeca-16-en-4,6-diyne-3,9,10-triolC17H26O3[α]D25=-16.0 (c 0.1, MeOH)Source of chirality: (−)-Diethyltartrate, (+)-DiethyltartrateAbsolute configuration: (3S,9S,10S)