The chemistry of terpenes. Part XXI. By-products from the epoxidation of (+)-car-3-ene with acetonitrile–hydrogen peroxide

Abstract

Epoxidation of (+)-car-3-ene (1) with acetonitrile–hydrogen peroxide afforded, besides (+)-3α,4α-epoxycarane (2), minor amounts of (+)-3α,4α-epoxycaran-2-one (3), (–)-3α,4α-epoxycaran-5-one (4), (–)-3α,4α-epoxycaran-2α-ol (5), and (+)-3α,4α-epoxycaran-5α-ol (6). Reduction of the epoxy-alcohol (5) with lithium aluminium hydride gave (–)-carane-2α,3α-diol (7), also obtained from (+)-car-2-ene (8) and permanganate. Reduction of the epoxy-ketone (3) with borohydride gave only (–)-3α,4α-epoxycaran-2β-ol (9), which with lithium aluminium hydride afforded (–)-carane-2β,3α-diol (12). Oxidation of the epoxy-alcohol (6) yielded the epoxyketone (4) which, on reduction with borohydride, gave (+)-3α,4α-epoxycaran-5β-ol (13), isolated as its monohydrate.