Diastereoselective Synthesis of C-Glycosylated Amino Acids with Lactams as Peptide Building Blocks

Readily available by lipase-catalyzed kinetic resolution or from a chiral pool, beta-, gamma-, and delta-lactams can be used as peptide building blocks for the synthesis of C-glycosylated amino acids 1. By reaction with glycosyl dianions, metabolic stable glycosylated amino acids can be prepared diastereoselectively. Ac=acetyl; Bn=benzyl; Boc=tert-butoxycarbonyl; R=Et, Bn; R'=H, alkyl; n=1-3.     

Wasserzusatz

Ohne Zusammenfassung     

Diastereoselective synthesis of homologous bicyclic lactams--potential building blocks for peptide mimics

Bicyclic lactams serve as building blocks for the synthesis of conformationally restricted peptides. A route to these building blocks is described. They can serve as cis- and trans-peptide bond surrogates. Due to the de novo synthesis, both enantiomeric forms of these products can be produced. Key steps are a lipase-catalyzed saponification of oximes and a highly diastereoselective cyclization utilizing phenylselenyl bromide. In addition, attachment to a solid support has been achieved.     

Bestimmung, Trennung und Eigenschaften der unverseifbaren Bestandteile der Fette

Ohne Zusammenfassung     

Stereoselective synthesis of (+/-)-rocaglaol analogues

An intramolecular hydroxy epoxide opening was used to access the cyclopenta[b]benzofuran ring system of the natural product rocaglaol (2). Our route allowed the stereocontrolled preparation of the rocaglaol derivative (+/-)-(1S*,3S*,3aR*,8bS*)-3b. The synthesis of the (+/-)-(3R*)-epimer of 3b was also achieved. Our strategy is well-suited for the production of analogues with variation of the western ring. [reaction: see text]