An asymmetric [2+2+2] cycloaddition of an alpha,omega-diyne, possessing ortho-substituted aryl groups on its terminus, and a monoalkyne with oxygen functionalities gave various axially chiral teraryl compounds. The coupling proceeded with extremely high enantio- (>99.5% ee) and diastereoselectivities (dl/meso = >95/5) when catalyzed by an iridium-chiral phosphine complex. As the products were readily transformed into diol compounds by deprotection without racemization, the present procedure provides access to a new chiral pool of diol compounds with C2 symmetry.

Substitution of fluorine atoms on an organic molecule makes it possible to modify the molecular orbital and electron density of the surface without changing its molecular shape. Point‐fluorinated analogues of the sex pheromone of the male African sugarcane borer were synthesized in optically active forms and their pheromone activities were investigated using an EAG test. The EAG activity of these point‐fluorinated pheromone analogues indicates that the point of fluorination has a critical influence on the pheromone activity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Diastereoselective syntheses O 0031Iridium Complex Catalyzed Highly Enantio-and Diastereoselective [2 + 2 + 2] Cycloaddition for the Synthesis of Axially Chiral Teraryl Compounds. -The title reaction of diynes and alkynes with oxygen functionalities gives various axially chiral teraryl compounds with extremely high enantio-and diastereoselectivities. As the products are readily transformed into diol compounds by deprotection without racemization, the present procedure provides access to a new chiral pool of diol compounds with C2 symmetry. -(SHIBATA*, T.; FUJIMOTO, T.; YOKOTA, K.; TAKAGI, K.; J. Am. Chem. Soc. 126 (2004) 27, 8382-8383; Dep. Chem., Sch. Sci. Eng., Waseda Univ., Shinjuku, Tokyo 169, Japan; Eng.) -S. Adam 45-025