170641-13-1Relevant 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.
Syntheses of ethyl 3-deoxy-3,3-difluoro-D-arabino-heptulosonate and analogues
Li, Yuan,Drew, Michael G.B.,Welchman, Elizabeth V.,Shirvastava, Rajeev K.,Jiang, Shende,Valentine, Roy,Singh, Gurdial
, p. 6523 - 6531 (2007/10/03)
The difluorinated analogues of 3-deoxy-D-arabino-heptulosonic acid (DAH) 12, 24 and its enantiomer have been synthesised from D- and L-erythrose via a Reformatsky reaction which gave a mixture of diastereoiosmers in favour of the anti isomer.
β-lactams from D-erythrose-derived imines: A convenient synthesis of 2,3-diamino-2,3-dideoxy-d-mannonic-acid derivatives
Storz, Thomas,Bernet, Bruno,Vasella, Andrea
, p. 2380 - 2412 (2007/10/03)
The D-manno-configured N-anisylated β-lactam 40, the β-lactam carboxylic acids 4 and 43, and the corresponding phosphonic-acid isosters 49 and 50 have been synthesized from D-glucose in 8-10 steps, respectively. None of these compounds exhibited a significant inhibitory activity in vitro against the sialidases of Vibrio cholerae, Salmonella typhimurium, Influenza A (N9), and Influenza B virus. Cycloaddition of the in situ generated imines derived from the D-erythroses 6, 16, and 17 with the ketene from mesyloxyacetyl chloride (20) gave the 2-mesyloxy-D-hexono-1,3-lactams 25, 27a/b, 28a/b/c, and 29 in 23, 69, 57, and 90% yield, respectively (Scheme 3). Transformation of 27a/b and 29 (> 85%) to the corresponding azides, followed by oxidative N-deprotection, gave 30a/b (45%) and 34 (80%). Subsequent alkylation of the ring N-atom in 31a with benzyl bromoacetate and dibenzyl (triflyloxymethyl)phosphonate 46 gave the carboxylate 41 (77%) and the phosphonate 47 (55%; Schemes 4 and 5). Hydrogenolysis of 41 gave the β- lactam amino acid 43, besides its hydrolysis product 44. Reductive N- acylation of the azido group in 41 (93%), followed by hydrogenolytic debenzylation, yielded the 2-trifluoroacetamido N-(carboxymethyl)-β-lactam 4 (56%). Similarly, 47 gave the 2-trifluoroacetamide 48 (89%), and hence, the 2-amino-N-(phosphonoylmethyl)-β-lactams 49 (40%) and 50, resulting from deacylation of 49 (14%). Aminolysis and carbamoylation of the protected β- lactams 31a and 35 led to the 2,3-diamino-2,3-dideoxy-D-mannonamides 51 and 53, respectively (Scheme 6).
