A new synthesis of the enantiomers of ipsdienol, the pheromone of the IPS bark beetles
摘要:
The enantiomers (approximately 96% e.e.) of ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol, 1a) were synthesized from the enantiomers of serine (5) in 16-21% overall yield in 8 steps.
A new synthesis of the enantiomers of ipsdienol, the pheromone of the IPS bark beetles
摘要:
The enantiomers (approximately 96% e.e.) of ipsdienol (2-methyl-6-methylene-2,7-octadien-4-ol, 1a) were synthesized from the enantiomers of serine (5) in 16-21% overall yield in 8 steps.
Periselective and enantioselective carbonyl–ene reaction of isoprene with fluoroalkyl glyoxylate catalysed by modified binaphthol–titanium complex: asymmetric catalytic synthesis of enantiomerically pure ipsdienol
作者:Masahiro Terada、Koichi Mikami
DOI:10.1039/c39950002391
日期:——
The asymmetric reaction of trifluoroethyl glyoxylate 3d with isoprene 4 catalysed by the modified binaphtholâtitanium complex 2b provides the ene product 5d in high periselectivity (92%) and complete enantioselectivity, which can be converted to ipsdienol 1, a component of the aggregation pheromone of the bark beetle, genus lps, in enantiomerically pure form.
The hetero Diels-Alder reaction of nonactivated conjugated dienes 1 with arylglyoxals 2 and glyoxylate esters 7 proceeded enantioselectively in the presence of a catalytic amount of cationic chiral BINAP-palladium or -platinum complexes and 3 Angstrom molecular sieves (MS3A). The addition of MS3A effectively improved the enantioselectivity of the reaction. Excellent ee's were obtained from the reactions of 2,3-dimethyl-1,3-butadiene (1a) and 1,3-cyclohexadiene (1d) with dienophiles 2 and 7. The square-planar structure of [Pd(S-BINAP)(PhCN)(2)](PF6)(2) was determined by X-ray diffraction, and a chiral induction model involving the square-planar palladium complex coordinated with BINAP and a dienophile is proposed.