Studies On The Total Synthesis Of Anditomin

Anditomins are fungal meroterpenoids isolated from Aspergillus variecolor and have unique,highly oxygenated 7/6/6/5/7/5 chemical structure with five quaternary carbon chiral centers,a five-membered lactone and a seven-membered lactone,and a complex bridged-ring system.So far,there is no report on the total synthesis of natural products of anditomin.The complex bridged-ring system is undoubtedly a great challenge in the synthesis.According to the biogenic synthesis pathway of anditomin,we designed a synthetic route for the core skeleton of anditomin by using the positive carbon ions induced tandem cyclization of polyenes accompanied by 1,2-transfer rearrangement of carbonyl groups.The highlight of the design is that multiple rings are constructed at one time,and the complex bridged-ring system is constructed by 1,2-transfer rearrangement of carbonyl groups.Firstly,we studied the synthesis of tricyclic core skeleton of CDE in the complex bridged-ring system of anditomin.We designed to construct bicyclo[2.2.2]octane skeleton by Diels-Alder reaction,and then constructed C ring through aldol condensation reaction.Finally,the hydroxyl group was eliminated under the action of Burgess reagent,and carbonyl 1,2-migration rearrangement was induced to complete the synthesis of tricyclic core skeleton of anditomin CDE.Burgess reagent eliminates hydroxyl induced carbonyl 1,2-migration rearrangement and completes the construction of tricyclic core skeleton of anditomin CDE,which is the highlight of this study.On the basis of the above work,we studied the synthesis of the four ring core skeleton of anditomin CDEF,we designed to construct the three ring framework of DEF by one-step Diels-Alder reaction,and then construct the C ring by aldol condensation reaction.Finally,under the action of Burgess reagent,hydroxyl groups were eliminated and carbonyl 1,2-rearrangement was induced to complete the synthesis of anditomin CDEF four ring core skeleton,which is still under study.