Selective oxidn. of unsaturated hydrocarbons - using singlet oxygen generated by electric discharge

摘要

Selective oxidn. of unsaturated hydrocarbons is effected with a stream of O2 in the ground state contg >=1 10% metastable (singlet) oxygen produced by an electric discharge. The reaction is effected at 1-15 torr and at a temp. such that the vapour pressure of the hydrocarbon or the solvent contg. it is at least equal to the O2 pressure. The process is esp. useful for converting cyclopentadiene to the corresp. 1,4-endoperoxide, which can then be reduced stereoselectively to give the pure cis isomer of 2-cyclopentane-1,4-diol (I). The latter is an intermediate in the synthesis of prostaglandins with the natural configuration. The oxidn. process requires shorter reaction times than photochemical processes and avoids the use of sensitisers.