[(1R,2S)-2-carboxy-1-[[2-(3,4-dihydroxycyclohexyl)acetyl]oxymethyl]-2-[(2-formyl-5,6,7,8-tetrahydro-1H-indolizine-1,2,3,5,6,7,8,8a-octaid-3-yl)amino]-1-methyl-ethyl]-hydroxy-oxido-sulfonium