Regio- and stereocontrol in the intramolecular nitrile oxide cycloaddition to 2-furylthiol- and 2-furylmethanethiol derivatives.
                                
                                    
                                        作者:Rita Annunziata、Mauro Cinquini、Franco Cozzi、Laura Raimondi、Giulia Licini                                    
                                    
                                        DOI:10.1016/s0040-4020(01)80910-8
                                    
                                    
                                        日期:——
                                    
                                    A series of 2-furyl and 2-furylmethyl substituted nitrosulphides with a proper chain length were prepared and showed to undergo a totally regiocontrolled intramolecular furan-nitrile oxide cycloaddition to give cis-fused products in high yield. Insertion of a stereocenter on the cycloaddends did not allow satisfactory control of the absolute stereochemistry of the reaction. Enantiomerically enriched products (e.e. less-than-or-equal-to 95%) were obtained by a kinetic resolution process involving oxidation of the sulphide cycloadducts to the corresponding sulphoxides.