Chiral synthons from campholenaldehyde: enantiospecific synthesis of diquinane and linear triquinanes

Enantiospecific syntheses of diquinane and linear triquinanes were accomplished, starting from the readily available α-campholenaldehyde employing a Nazarov reaction as the key step.

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1-[(4S)-4-(2-Methoxyethyl)-5,5-dimethylcyclopent-1-en-1-yl]prop-2-en-1-oneC13H20O2[α]D21=+7.4 (c 9.0, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (4S′)

(S)-7-(2-Methoxyethyl)-8,8-dimethylbicyclo[3.3.0]oct-1(5)-en-2-oneC13H20O2[α]D26=+2.1 (c 1.7, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (7S)

1-[(1R,5R,7R)-7-Methoxy-4,4-dimethylbicyclo[3.3.0]oct-2-en-3-yl]prop-2-en-1-oneC14H20O2[α]D21=-99.7 (c 2.0, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R′,5R′,7R′)

(1S,8R,10R)-10-Methoxy-7,7-dimethyltricyclo[6.3.0.02,6]undec-2(6)-en-5-oneC14H20O2[α]D26=-43.1 (c 3.8, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1S,8R,10R)

(1R,2S,6S,8R,10R)-10-Methoxy-7,7-dimethyltricyclo[6.3.0.02,6]undecan-5-oneC14H22O2[α]D27=-87.7 (c 0.5, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,2S,6S,8R,10R)