Crystal structures of two 1,2,3,4-tetrahydronaphthalenes obtained during efforts towards the total synthesis of elisabethin A

Abstract

The two substituted 1,2,3,4-tetrahydronaphthalenes, methyl (R)-3-{(1R,4S)-6-methoxy-4,7-dimethyl-5,8-bis[(triisopropylsilyl)oxy]-1,2,3,4-tetrahydronaphthalen-1-yl}butanoate, C36H66O5Si2, (2), and methyl (E)-3-{(1R,4S)-8-hydroxy-6-methoxy-4,7-dimethyl-5-[(triisopropylsilyl)oxy]-1,2,3,4-tetrahydronaphthalen-1-yl}acrylate, C26H42O5Si, (8), crystallize in the Sohncke space groups P212121 and P21, respectively, with the absolute structure determined on the basis of anomalous dispersion effects. The configurations of the stereo centres in the 1,2,3,4-tetrahydronaphthalene moiety of (2) and (8) are the same, and the conformation of the non-aromatic part of the ring system is nearly identical. In the crystal of (2), weak non-classical C—H...O interactions consolidate the packing, whereas in (8), intermolecular O—H...O hydrogen-bonding interactions of medium-to-weak strength direct the molecules into Z-shaped strands extending parallel to [010].

Keywords

• crystal structure
• marine diterpenoids
• absolute configuration
• fused ring system
• disorder