Enantioselective Synthesis of Non‐Natural Aromatic α‐Amino Acids

Abstract

The authors recently investigated Heck coupling reactions of vinyl glycinol 9 with different aryl halides. It was noted in the new study that the previously reported signs of the optical rotations of compounds 12a and 12f are wrong and must be corrected as follows: (S)-[1-hydroxymethyl-3-(6-methoxy-napthalen-2-yl)-propyl]-carbamic acid 9H-fluoren-9-ylmethylester 12a: [a] 20 D = + + 10.48 (c = 0.5, DMF) instead of À10.58 and (S)-(3-anthracen-9-yl-1-hydroxymethyl-propyl)-carbamic acid 9H-fluoren-9-ylmethylester 12f: [a] 20 D = + + 30.58 (c = 0.5, DMF) instead of À30.78. The authors apologize for any inconvenience caused by these errors.

Tripeptides from Synthetic Amino Acids Block the Tat–TAR Association and Slow Down HIV Spread in Cell Cultures

“…Tat peptide 18 (Thermo Electron Corporation, 10 nm) was titrated either with TAR RNA 19 or with TAR RNA 20. The following concentration range for the RNA was chosen: 0, 4, 6,8,10,12,14,16,20,30,40 nm. The blank contained only TK buffer.…”

“…, 0.19 mmol) by standard procedures as published earlier. [10] After removal of the last Fmoc group, the resin was washed with DCM and dried in vacuo. The resin was then treated with TFA (1650 mL), thioanisol (100 mL), water (100 mL), phenol (50 mg), and EDT (50 mL).…”

“…We have started a research program targeted towards synthetic aamino acids that carry aromatic and heteroaromatic side chains. [10] Such residues might contribute to RNA binding either through stacking with exposed bases or through hydrogen bonding. The main purpose of the peptidic backbone is to assemble several side chains with polar or hydrophobic properties in a chemically efficient way and to allow, if required, easy combinatorial variation.…”

Synthesis of Non‐Natural Aromatic α‐Amino Acids by a Heck Reaction

“…(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) avoid these problems, we had chosen a different strategy that relies on racemisation-proof transformations of a central enantiopure intermediate. [6] Derivatives of allylglycine [7] or vinylglycinol [8] fulfil such criteria. Compound 3 for example, after hydroboration of its alkene moiety, reacts with a broad range of aryl and heteroaryl bromides in a Suzuki cross-coupling reaction.…”

“…Compound 3 for example, after hydroboration of its alkene moiety, reacts with a broad range of aryl and heteroaryl bromides in a Suzuki cross-coupling reaction. [6] Herein we report on the Heck reactions of vinylglycinol 3 for the attachment of aromatic side-chains. The resulting products were converted into amino acids and finally into RNA-binding tripeptides of the general structure H 2 N-()-Arg-X-()-Arg-CONH 2 .…”