The Total Synthesis Of Homofarnesenes And The Synthetic Studies Of (-)-Retigeranic Acid A

Homofarnesenes were isolated from Solenopsis invicta by Wilson in 1959.Homofarnesenes are two different types of chain polyene compounds,which are Homofarnesene 1a and 1b.Retigeranic acid A was isolated from the Solenopsis invicta genus by Seshadri's group in 1965.Its structure was determined by X-ray.Its basic skeleton consists of a trans-niranane structure and three five-membered thick rings with 8 chiral centers on the skeleton.This dissertation consist of the total synthesis of Homofarnesenes and the synthetic studies of(-)-Retigeranic acid A.The total synthesis of HomofarnesenesUsing the elimination reaction of beta hydroxyl phosphonate as the key step,we have completed the total synthesis of Homofarnesenes with highly stereoselectivity.Using methyl glycolate as staring material,and through 9 steps such as the functional transformation,nucleophilic addition,alkylation and elimination of beta hydroxyl phosphonate and Wittig reaction,the total synthesis of Homofarnesene 1a was achieved by 15% yield and ZE:EE=7.5:1 stereoselectivity.Using dimethel acetonylphosphonate as staring material,and through 5 steps such as nucleophilic addition,alkylation and elimination of beta hydroxyl phosphonate,the total synthesis of Homofarnesene 1b was achieved by 37% yield and EE:ZE=8:1 stereoselectivity.Though the total synthesis of Homofarnesene 1a and 1b,we found a new and stereoselective method to build tetra-substituted ethylenes.The synthetic studies of Retigeranic acid AThrough the exploration of the two generation of synthetic routes,we have not completed the total synthesis of Retigeranic acid A,but we have constructed two key fragment compounds of Retigeranic acid A.Using 2-methyl-1,3-cyclopentanedione as staring material,and through 12 steps such as 1,4-addition,functional transformation,oxidation reduction cyclization reaction and Huang min lon-Reduction reaction,6-5-5 three thick ring fragment was completed by 8% yield.Using(-)-limonene as staring material,and through 5 steps such as selective epoxidation,catalytic hydrogenation,chlorinated rearrangement and halogen replacement,five membered ring precursors with chiral isopropyl group was synthetized by 31% yield.The two key fragment compounds were butted with 1,4-addition,and the screening of docking conditions was still in progress.