950601-14-6Relevant academic research and scientific papers
Asymmetric formal trans -dihydroxylation and trans -aminohydroxylation of α,β-unsaturated aldehydes via an organocatalytic reaction cascade
Albrecht, Lukasz,Jiang, Hao,Dickmeiss, Gustav,Gschwend, Bjoern,Hansen, Signe Grann,Jorgensen, Karl Anker
supporting information; experimental part, p. 9188 - 9196 (2010/08/21)
This study demonstrates the first formal asymmetric trans-dihydroxylation and trans-aminohydroxylation of α,β-unsaturated aldehydes in an organocatalytic multibond forming one-pot reaction cascade. This efficient process converts α,β-unsaturated aldehydes into optically active trans-2,3-dihydroxyaldehydes and trans-3-amino-2-hydroxyaldehydes with the aldehyde moiety protected as an acetal. The elaborated one-pot protocol proceeds via the formation of 2,3-epoxy and 2,3-aziridine aldehyde intermediates, which subsequently participate in a novel NaOMe-initiated rearrangement reaction leading to the formation of acetal protected trans-2,3-dihydroxyaldehydes and trans-3-amino-2-hydroxyaldehydes in a highly stereoselective manner. Advantageously, this multibond forming reaction cascade can be performed one-pot, thereby minimizing the number of manual operations and purification procedures required to obtain the products. Additionally, for the purpose of trans-aminohydroxylation of the α,β-unsaturated aldehydes, a new enantioselective aziridination protocol using 4-methyl-N-(tosyloxy) benzenesulfonamide as the nitrogen source has been developed. The mechanism of the formal trans-dihydroxylation and trans-aminohydroxylation of α,β-unsaturated aldehydes is elucidated by various investigations including isotopic labeling studies. Finally, the products obtained were applied in the synthesis of numerous important molecules.
