A short synthesis of (S)-(+)-siphonodiol

A short synthesis of the enantiomer of the polyacetylenic natural product siphonodiol is described. The synthesis is based on the strategy of taking advantage of the hidden symmetry of the target molecule and minimizing the use of protecting groups, thereby reducing the total number of steps and increasing the overall efficiency.

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(S)-Undeca-3,5,10-triyne-1,2-diolC11H12O2Ee = >98%[α]D23=+41.4 (c 0.06, CHCl3)Source of chirality: d-mannitolAbsolute configuration: (S)

(S)-2,2-Dimethyl-4-nona-1,3,8-triynyl-[1,3]dioxolaneC14H16O2Ee = >98%[α]D23=+58.3 (c 0.04, CHCl3)Source of chirality: d-mannitolAbsolute configuration: (S)

(S)-11-Bromo-undeca-3,5,10-triyne-1,2-diolC11H11O2BrEe = >98%[α]D23=+24 (c 0.009, CHCl3)Source of chirality: d-mannitolAbsolute configuration: (S)

(S)-(+)-SiphonodiolC23H24O2Ee = >98%[α]D23=+6.5 (c 0.004, CHCl3)Source of chirality: d-mannitolAbsolute configuration: (S)