Neue Wege zur Nutzung von Aminosäuren als chirale Bausteine in der organischen Synthese

Amphoteric Amino Aldehydes Enable Rapid Assembly of Unprotected Amino Alcohols

“…[3] The recourse to protecting groups has also produced complications in metal-mediated addition reactions to chiral a-amino aldehydes, as delicate tuning of the nitrogen substituent is required to selectively minimize the competing governance of stereocontrol by either chelation or nonchelation models. [4] Furthermore, the removal of the protecting groups from the amino alcohol product is often not trivial. This limitation is not restricted to the synthesis of amino alcohols from amino aldehydes.…”

Metal‐Free Ring‐Expansion Reaction of Six‐membered Sulfonylimines with Diazomethanes: An Approach toward Seven‐Membered Enesulfonamides

“…2-(2-Amino-1-phenylethyl)phenol ( 7), which is an important structural unit in the agricultural and pharmaceutical agents, [19] was easily derived from the cyclic sulfonamide 6 in 85 %y ield. Hydrogenation of 3a using Pd/C gave the cyclic sulfamate 6 in 90 %yield.…”

“…Notably,1 -naphthyl Ntosylhydrazone participated in the reaction to give the corresponding product 3p in 81 %yield. Theheteroaromatic 3-thiophenyl N-tosylhydrazone provided the expected products 3q in 45 %y ields (entry 17), but the 2-furanyl or 2thiophenyl N-tosylhydrazones failed (entries [18][19]. To our delight, when R 2 = methyl, the corresponding products 3rt were afforded in moderate yield (entries 20-22).…”

Dimethyl [(2R,3R,5S)‐5‐phenylmorpholine‐2,3‐diyl]diacetate as a Designer Substrate in the Syntheses of Important Heterocyclic Scaffolds

“…[26] The existing routes for the preparation of this structural unit include the derivitization of amino acids, [27] asymmetric hydrogenation of an enaminoketone, [28] the Sharpless aminohydroxylation reaction [29] , Lewis acid promoted coupling reactions of oxazines with nucleophiles, [30] catalytic Mannich type reactions of aalkoxy enolates to imines, [31] and opening of epoxides with amine nucleophiles. [32] However, most of these approaches give different syn and anti ratios and enantioselectivity.…”