Isolation of ozonides front gas-phase ozonolyses of terpenes

Ozonolyses of (-)-beta-pinene (1) and of (+)-sabinene (6) in the gas phase afforded the corresponding ozonides 6,6-dimethylbicyclo[3.1.1(1,5)]heptane[2-spiro-3]-1,2,4-trioxolane (2) and 5-isopropylbicyclo[3.1.0(1,5)]hexane[2-spiro-3]-1,2,4-trioxolane (7), which were isolated as mixtures of two diastereomers each. Major products were the corresponding ketones 6,6-dimethyl-2-oxobicyclo[3.1.1(1,5)]heptane (3) and 5-isopropyl-2-oxobicyclo[3.1.0(1,5)]hexane (8). Additional products were the lactones 7,7-dimethyl-2-oxa-3-oxobicyclo[4.1.1(1,6)]octane (4) and 7,7-dimethyl-3-oxa-2-oxobicyclo[4.1.1(1,6)]octane (5) derived from P-pinene (1) as well as 6-isapropyl-2-oxa-3-oxobicyclo[4.1.0(1,6)]heptane (9) and 6-isopropyl-3-oxa-2-oxobicyclo[4.1.0(1,6)]heptane (10) derived from sabinene (6).