During our studies of elaborating chiral 3-pyrrolines containing the formamidine moietys into various 2-substituted pyrrolidines,'we required considerable quantities of 2, 6-dihydropyrrole 1 (Scheme I). We had previously utilized commercially available 3-pyrroline which contained 15% pyrrolidine? and this required chromatographic separation at the formamidine stage to reach pure 2. More recently, however, 1 is available in only 65% purity? and it is possible ...
