Abstract The chlorinative ene-type reaction of isoprenoids (1→ 2) has been performed by electrolysis in CH 2 Cl 2-H 2 O-NaCl system. The reaction provides useful allylic chlorides 2 for terpene synthesis in high yields and is affected strikingly by the nature of halide ions and solvents. dl-Theaspirane 21 was prepared from α-dihydroionol via the electrolysis.
