But-2-ene-1,4-diamine and But-2-ene-1,4-diol as Donors for Thermodynamically Favored Transaminase and Alcohol Dehydrogenase-Catalyzed Processes

Abstract

cis- and trans-But-2-ene-1,4-diamine have been prepared and efficiently applied as sacrificial cosubstrates in enzymatic transamination reactions. The best results were obtained with the cis-diamine. The thermodynamic equilibrium of the stereoselective transamination process is shifted to the amine formation due to tautomerization of 5Hpyrrole into 1H-pyrrole, achieving high conversions (78- 99%) and enantiomeric excess (up to >99%) by using a small excess of the amine donor. Furthermore, when the reaction proceeded, a strong coloration was observed due to polymerization of 1H-pyrrole. A structurally related compound, cis-but-2-ene-1,4-diol, has been utilized as cosubstrate in different alcohol dehydrogenase (ADH)-mediated bioreductions. In this case high conversions (91-99%) were observed due to a lactonization process. Both strategies are convenient from both synthetic and atom economy points of view in the production of valuable optically active products