Preparation Of Multisubstituted Cyclopropane Fused ?-Butyrolactones And Their Formal [3+2] Cycloaddition Reactions With Aldehydes/Ketones

In this thesis,preparation of the multisubstituted cyclopropane fused ?-butyrolactones and their formal [3+2] cycloaddition reactions with aldehydes/ketones were studied.Reduction of trans-2-aroyl-3-arylcyclopropane-1,1-dicarboxylate using 1.0 equiv sodium borohydride?in methanol,at room temperature?proceeded to afford the corresponding alcohol,which upon intramolecular transesterification gave the multisubstituted cyclopropane fused ?-butyrolactones: r-1,cis-4,cis-6-diaryl-2-oxo-3-oxabicyclo[3.1.0]hexane-1-carboxylate by treatment with 0.3 equiv p-TsOH in toluene at50 or 25 ?C in good to high yields with excellent diastereoselectivity.Under the catalysis of 1 % mol Sn?OTf?₂,the formal [3+2] cycloaddition reaction of r-1,cis-4,cis-6-diaryl-2-oxo-3-oxabicyclo[3.1.0]hexane-1-carboxylate with 1.1 equiv aldehydes/ketones in 1,2-dichloroethane?DCE?at 40 ?C produced multisubstituted3-oxohexahydrofuro[3,4-c]furan-3a-carboxylate in good to high yields with excellent diastereoselectivity.The relative configurations of the cycloaddition products are r-3a,cis-1,trans-4,trans-6,cis-6a.The 1 % mol loading of catalyst and almost stoichiometric aldehydes/ketones are rare available in the reported related cycloaddition reactions.All the products were well characterized by ¹H NMR,¹³C NMR,IR and HRMS.The relative configurations of some typical products were determined by COSY,NOESY and X-ray crystallographic analysis.