Study On The Asymmetric Syntheses Of Two Kinds Of Insect Sex Pheromone

Tea and corn are important crop plants in China,and their pest control are mainly through chemical pesticides,traditionally.The tea tussock moth is a kind of tea pest,which can affect the tea quality seriously and cause heavy economic loss to the tea industry.The American western corn rootworm is the main pest of corn in America,and its larvae swallows corn rootstock,which lead to crop failure and death and decrease the corn yield greatly.To achieve the sustainable development of the green environment,using insect sex pheromone to control insect reducing the use of chemical pesticides,insect sex pheromone has been accepted as the characteristics of high sensitivity,low toxicity and the environment friendly.The synthesis of the sex pheromones of tea tussock moth and American western corn rootworm have been achieved in this paper based on the asymmetric induction.Herein,we have developed appropriate for industrialized production of an efficient total synthetic route.There are the main achievements in this thesis.1.The sex pheromones of tea tussock moth and American western corn rootworm have been accomplished in this thesis.The syntheses of 69 compounds were completed,of which42 compounds are new ones.All these compounds were characterized by ¹H NMR and ¹³C NMR,the chirality of 50 chiral compounds were measured by polarimeter.Some important intermediates and all the target molecules were characterized by HRMS.The enantiomeric excess values of chiral molecules after the Evan’s asymmetric induction were tested by HPLC.2.The construction of C-C skeleton was furnished through Julia olefination;Evans asymmetric alkylation was adopted for the structure of chiral center.Altogether,the syntheses of three routes of the sex pheromone of（R）-configuration tea tussock moth were completed.（1）The I route of the sex pheromone of（R）-configuration tea tussock moth was completed in25%overall yield（11steps）from cheap 4-benoxybutyric acid.The C-C skeleton was constructed by using Julia olefination and the chiral center was built by Evans asymmetric alkylation.（2）The IIA route of the sex pheromone of（R）-configuration tea tussock moth was given in 30%overall yield（7 steps）from ethyl 4-bromocrotonate;the IIB route of the sex pheromone of（R）-configuration tea tussock moth was developed in 26%overall yield（8 steps）from cheap 4-bromobutyric acid.（3）The III route of the sex pheromone of（R）-configuration tea tussock moth was accomplished in 36%overall yield（5 steps）by（S）-citronellal and 1,7-heptanediol.3.Based on resource chemistry,the total synthesis of the sex pheromone of（S）-configuration tea tussock moth was completed in 29%overall yield（8 steps）from a large-scale chiral molecule which was recycled from the degradable industrial waste of steroidal sapogenin.Similarly,the C-C skeleton of route was built by Julia olefination.Thus,two different configuration sex pheromone of（R）-configuration tea tussock moth could be provided.It will be helpful to study the difference between them.It is worth to be noted that our method provides a new synthesis of R-4-benoxy 3-methylbutanal.4.Based on Julia-Lythgoe olefination to construct of C-C skeleton,and chiral epoxide ring-opened method and Evan’s asymmetric alkylation,four stereoisomers of the sex pheromones of American western corn rootworm were synthesized in 24–29%overall yield in six steps,respectively.5.In the synthesis of two kinds of insect pheromones,Evans asymmetric alkylation showed very good stereo-selectivity,the ee value of chiral molecule was characterized by HPLC,the ee is as high as 95%.It proved that the method could be expanded to the preparation of analogues.6.In the syntheses of two kinds of insect pheromones,the Julia olefination was used many times.Although,it generally gave Z/E mixture,these results didn’t affect target molecule because of C-C single bond the target molecule.Based on construction of carbon skeleton by Julia olefination and chiral centers by Evan’s asymmetric alkylation in this manuscript,the synthesis of the sex pheromone of the tea tussock moth and American western corn rootworm were completed.We realized the gram-scale preparation of the sex pheromone of the tea tussock moth and American western corn rootworm.This quanlity of substances are sufficient to the field experiments.All these results will be helpful to the synthesis of other insect sex pheromones and providing theoretical basis.