Synthesis of the enantiomers of lasiol, an acyclic monoterpene alcohol in the mandibular gland secretion of the male ants, Lasius meridionalis.
(2S,3S)-(-)-Lasiol (2,3,6-trimethyl-5-hepten-1-ol, 1) and its antipode were synthesized from cis-4,5-dimethylcyclohexene oxide (3) by employing asymmetric cleavage of the epoxy ring with a chiral lithium amide derived from 4 to give optically active cis-4,5-dimethyl-2-cyclohexen-1-ol (5) as the key-step.
Lithium diisopinocampheylamide: a new and highly effective chiral catalyst in the enantioselective deprotonation of meso-epoxides
Abstract α-Pinene based novel chiral lithium amides have been used for the catalytic enantioselective deprotonation of cyclohexene oxide. An enantiomeric excess of up to 95% for ( R )-2-scyclohexen-1-ol was achieved with lithium (−)- N , N -diisopinocampheylamide. A systematic study shows that the isopinocampheyl moiety plays an important role in achieving high enantioselectivity.
Energy skin effect of propellant particles in Electrothermal-Chemical Launcher
A numerical model of the radiation has been employed by a Monte Carlo method and statistical physics to simulate the process of a capillary plasma source for Electrothermal-Chemical (ETC) Launcher. The effect on propellants with different physical parameters is discussed. The plasma-propellant interaction is also discussed when combined with a thermal model. Results show that radiant energy only causes a small field around the plasma injector in the propellant bed. The responses of energy flux and propellant particles on radiation are both in the order of picosecond. The strong instantaneous radiation is responsible for the transmission of energy to the propellant particles leading to ignition. Compared with conventional ignition, the energy absorbed by propellant particles is used to increase quickly the temperature in the surface layer of propellant particles. This energy skin effect in the propellant particle surface appears to be the main cause of plasma ignition.