Development of new chiral auxiliary from the Diels-Alder adduct endo-tricyclo[6.2.1.02,7] undeca-4 ,9-dien-3 ,6-dione

Abstract

Stereochemistry control is very important in organic synthesis and it is a basic challenge in asymmetric synthesis. An approach widely used is making use of chiral auxiliary compounds. In this work it is showed the synthesis of highly optically pure rigid polycyclic compounds from the Diels-Alder adduct 1 . Compounds 1 - 3 were prepared as described by Ito et. al. [1]. The alcohol (-)- 3 was obtained by biotransformation of diketone 2 with Mucor ramosissimus, e.e.>99% (60%). The polycyclic halides 4 - 6 were synthesized (60-97%) after treatment of alcohol (-)- 3 with NBS, NIS and, NCS in dichloromethane, respectively. Compound 7 was prepared by reaction with p-toluenesulfonic acid, whilst 8 was prepared by treatment of (-)- 3 with m-chloroperbenzoic acid. The strained polycylic alcohols 9 - 13 will be achieved by reduction of ketones 4 - 8 with NaBH 4 . All compounds were identified by 1 H and 13 C NMR spectroscopy. Due to intrinsic rigidity of the synthesized polycyclic, they could be of use as chiral auxiliary agents. Prochiral substrates can be readily attached by many ways to C-3 or through hydroxyl group found in compounds 8 - 13 . The stereo-dirigent potential of these polycyclic can also be increased by directly or indirectly introduction of many groups at position C-3, or at adjacent positions to carbonyl or hydroxyl at C-3 and C-10.