A new approach to beta-functional phospholes. Application to the synthesisof a beta-CH2-CH2-bridged diphosphole disulphide

Protection of both the dienic system and the lone pair of phosphorus of 1-p henyl-3,4-dimethylphosphole by complexation with iron carbonyl groups allow the regiospecific deprotonation of one P-methyl substituent by lithium dii sopropylamide (LDA). The resulting anion exhibits versatile reactivity towa rds various electrophiles and can even undergo oxidative coupling with CuCl 2, thus providing an entry into the unprecedented beta-beta ' -bridged biph osphole system. Finally, the protecting iron carbonyl moieties can be clean ly removed in a two-step procedure involving reaction with sulphur and ceri um ammonium niti ate (CAN). (C) 2001 Elsevier Science B,V. All rights reser ved.