1-Azabicyclo[3.2.0]hept-2-ene-2-carboxylicacid, 3-([2,3'-bipyrrolidin]-4-ylthio)-6-(1-hydroxyethyl)-4-methyl-7-oxo-,[4R-[3(2S*,3'S*,4S*),4a,5b,6b(R*)]]-