Enantioselective syntheses of cis, syn, cis- and cis, anti, cis-linear triquinanes

Enantioselective syntheses of both cis, syn, cis- and cis, anti, cis-linear triquinanes, starting from the readily available (S)-campholenaldehyde, employing an RCM reaction-based cyclopentannulation strategy, are described.

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(1R,4R,5R)-4,7,8,8-Tetramethyl-4-vinylbicyclo[3.3.0]oct-6-en-3-oneC14H20O[α]D27=-30.0 (c 0.6, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,4R,5R)

(1R,2R,6R,8R)-2,9,9,10-Tetramethyltricyclo[6.3.0.02,6]undeca-3,10-dien-6-olC15H22O[α]D23=-24.0 (c 0.5, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,2R,6R,8R)

Methyl (1R,2R,5R)-2-(prop-2-enyl)-6,6,7-trimethylbicyclo[3.3.0]oct-7-ene-2-carboxylateC16H22O3[α]D24=+186.1 (c 6.1, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,2R,5R)

(1R,4S,5R)-6,6,7-Trimethyl-2-(methoxymethoxymethyl)-2-(prop-2-enyl)bicyclo[3.3.0]oct-7-en-3-oneC17H26O3[α]D22=+133.0 (c 3.6, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,4S,5R)

(1R,3S,4S,5R)-7,8,8-Trimethyl-4-(methoxymethoxymethyl)-4-(prop-2-enyl)-3-vinylbicyclo[3.3.0]oct-6-en-3-olC19H30O3[α]D23=+87.6 (c 1, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,3S,4S,5R)

(1R,2S,6R,8R)-9,9,10-Trimethyl-2-(methoxymethoxymethyl)tricyclo[6.3.0.02,6]undeca-4,10-dien-6-olC17H26O3[α]D23=+108.9 (c 1.4, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,2S,6R,8R)

(1R,2R,8R)-9,9,10-Trimethyl-2-(methoxymethoxymethyl)tricyclo[6.3.0.02,6]undeca-5,10-dien-4-oneC17H24O3[α]D23=+52.6 (c 0.7, CHCl3)Source of chirality: campholenaldehydeAbsolute configuration: (1R,2R,8R)