Formation of bromohydrins and epoxides from 4-hydroxy-2-oxabicyclo[3.3.0]oct-7-en-3-one and 9-hydroxy-7-oxabicyclo[4.3.0] non-4-en-8-one

Abstract

The hydroxy lactone 1 and the silylated derivative 8 react selectively with HOBr to give access to polyfunctional bicyclic systems such as the bromo ester 10. The lactone 3 or the corresponding derivative 20 react less selectively to give mixtures of compounds 16, 17, 18, 19, 21, 22. The hydroxybicyclo[4.3.0]nonenones 2 and 4 behave in a similar fashion to the lactone 3, reacting non-selectively with HOBr and m-chloroperbenzoic acid to produce a plethora of highly substituted bicyclo compounds 23–31, 33–39, 41 and 42. X-Ray crystal structures were obtained for four compounds, the diacetates 25 and 37 and the epoxides 26 and 27.