THE SYNTHESIS OF ETA(2)-BETA-VINYLPYRROLE COMPLEXES AND THEIR CONVERSION TO HIGHLY SUBSTITUTED INDOLES

A series of 4,5-eta(2)-Os (II)pentaammine-3-vinylpyrrole complexes are synthesized from the corresponding 1-methylpyrrole complex by an elec trophilic addition at the beta-carbon, C(3), of the pyrrole ring. Four independent synthetic routes to beta-vinylpyrrole complexes are descr ibed, each introducing different functionality on the pendant double b ond. The uncoordinated portion of these complexes chemically and struc turally resembles an aminodiene and as such readily undergoes Diels-Al der reactions with suitably activated dienophiles to generate the 5,6, 7,7a-tetrahydroindole nucleus. These tetrahydroindole complexes can be decomplexed and oxidized with DDQ to generate a series of highly func tionalized indoles.