A simple entry into enantiopure hydrindanes, hydroisoquinolones and diquinanes from 3,10-dioxygenated dicyclopentadienes: Application to the synthesis of (+)-coronafacic acid and a formal synthesis of (+)-coriolin

Abstract

A ready access to enantiopure 3,10-dioxygenated tricyclo[5.2.1.0^2,6]decane derivatives is reported. An efficient enzymatic kinetic resolution is employed through transesterification in the presence of lipase PS immobilized on Celite. Absolute configuration of the tricyclo[5.2.1.0^2,6]decan-10-one derivatives has been secured through correlation with (1R,2S)-1-aminoindan-2-ol. The promising utility of these enantiopure tricyclo[5.2.1.0^2,6]decane derivatives in synthesis has been demonstrated through the preparation of several optically pure cis-hydrindanes 15–18, employing the Haller–Bauer reaction as the key step for unbridging the trinorbornyl system. The cis-hydrindane (−)-16 has been further elaborated to the natural product (+)-coronafacic acid (+)-24. In an interesting sequence, cis-hydrindanone (+)-18 has been transformed into cis-hydroisoquinolones (+)-30 and (+)-33via photorearrangement of the derived oxaziridines 29 and 32, respectively. The hydroisoquinolones (+)-30 and (+)-33 can serve as useful enantiopure building blocks for the synthesis of complex indole alkaloids. Oxidative cleavage of the trinorbornene double bond in the tricyclo[5.2.1.0^2,6]decan-10-one derivative (−)-37 and functional-group adjustments leads to the optically pure diquinane (+)-38, an advanced intermediate in the total synthesis of (+)-coriolin (+)-34.