Diversity-Oriented Synthesis of Novel Trihalomethyl-Containing Spirochromeno[3,4-a](thia)pyrrolizidines and Spirochromeno-[3,4-a]indolizidines by One-Pot, Three-Component [3+2]-Cyclo­addition Reaction

Abstract Regio- and stereoselective methods for the synthesis of 6′-trifluoro(trichloro)methyl substituted spiro[acenaphthylene-1,11′-chromeno[3,4-a](thia)pyrrolizidin]-2-ones spiro[acenaphthylene-1,12′-chromeno[3,4-a]indolizidin]-2-ones have been developed based on three-component reaction 3-nitro-2-trifluoro(trichloro)methyl-2H-chromenes with azomethine ylides generated in situ from acenaphthenequinone cyclic α-amino acids. The cycloaddition proceeds under mild conditions ethanol or DMSO, only endo-isomers products cis-arrangement nitro trifluoromethyl groups are formed. relative configuration cycloadducts is reliably confirmed by X-ray diffraction analysis 2D NOESY spectroscopy.