Primary Amines Promoted Decyclization Transformations of p-Nitrobenzyl Ethers of Carbapenems
Ethylamine and ethanolamine react with 4-nitrobenzyl (4R,5S,6S)-3-[(2-furylmethyl)thio]-6-[(1R)-1hydroxyethyl]-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-en-2-carboxylate, leading to products of decylization of the β-lactam cycle with cleavage of the C<sup>7</sup>-N bond and simultaneous amidation in the ester part. In this transition of an anionoid nature, the enamine-imine rearrangement followed by stereoselective protonation provides the formation of enantiomerically pure pyrrolidine derivatives (2S,3R,4S)-N-ethyl-2-{(1S,2R)-1[(ethylamino)carbonyl]-2-hydroxypropyl}-4-[(2-furylmethyl)thio]-3-methyl-3,4-dihydro-2H-pyrrole-5-carboxamide and (2S,3R,4S)-4-[(2-furylmethyl)thio]-N-(2-hydroxyethyl)-2-[(1S,2R)-2-hydroxy-{[(2-hydroxyethyl)amino]carbonyl}propyl]-3-methyl-3,4-dihydro-2H-pyrrole-5-carboxamide.