Synthesis and absolute configuration of chiral (C<sub>3</sub>) cyclotriveratrylene derivatives. Crystal structure of (M)-(–)-2,7,12-triethoxy-3,8,13-tris-[(R)-1-methoxycarbonylethoxy]-10,15-dihydro-5H-tribenzo[a,d,g]-cyclononene
p. 127 °C, [α]D25–16.1°(CHCl3). The crystal and molecular structure of (–)-(3) have been determined by single crystal X-ray analysis: orthorhombic, a= 23.428, b= 22.165, c= 15.145 Å space group P212121, Z= 8. The M absoluteconfiguration has been ascribed to (–)-(3), on the basis of internal comparison with groups –CH(Me)CO2Me whose absolutestereochemistry is derived from that of (+)-(5b). Seven chiral