Stereochemistry of 1,3-dipolar cycloaddition reaction of azomethine ylidesderived from N-alkyl-N-(4-toluenesulphonyl) carbamoylmethyl phenanthridinium with olefinic dipolarophiles

A series of prepared N-alkyl-N-(p-toluenesulphonyl) bromoacetamides 1a-1b a fforded with phenanthridine quaternary phenanthridinium salts 2a-2b. These, when treated with triethylamine in dichloromethane, form azomethine ylides that udergo cycloaddition reaction with present activated olefinic C=C dou ble bond. This way pyrrolidino[1,2-f] phenanthridines 3-5 can be obtained. Their stereochemistry was studied by means of NMR spectroscopy. This family of phenanthridinium based ylides reacts very willingly with common olefini c dipolarophiles (dimethyl fumarate, dimethyl maleate or fumaronitrile) mor e or less stereoselectively. Some of the prepared racemic cycloadducts 3-5 were separated by HPLC on non-racemic cellulose-based sorbents with CD dete ction.