Stereodivergent Approach to β-Hydroxy α-Amino Acids from C₂-Symmetrical Alk-2-yne-1,4-diols

Abstract

[reaction: see text] A new stereodivergent route to erythro- and threo-beta-substituted serines from a common C(2)-symmetrical alk-2-yne-1,4-diol is described. Stereocontrol in such an acyclic system is achieved by taking advantage of symmetry. Stereoselective alkyne reduction to either (Z)- or (E)-olefin allows selection of the stereochemistry of alpha-carbon in the final amino acid by using a Pd(0)-catalyzed process. This strategy has been applied to the synthesis of (2S,3S)-3-hydroxyleucine.

Functionalization of terminal carbon atoms of hydroxyl terminated polybutadiene by polyazido nitrogen rich molecules

“…Spectrum A in figure 5 was recorded in CDCl 3 solvent and the peaks are shown in the figure. The chemical shift at δ = 1⋅62 with integration for two hydrogens corresponds to the hydrogens of the hydroxyl groups of the HTPB (Amador et al 2002). We have recorded spectrum B after addition of D 2 O to spectrum A solution.…”

An Ireland−Claisen Approach to β-Alkoxy α-Amino Acids

“…The importance of these molecules is reflected in the large number of reported synthetic routes to β-hydroxy-α-amino acids. Strategies include aldol reactions, enzymatic aldol reactions, reduction of amino β-keto esters, enantioselective dihydroxylation, enantioselective aminohydroxylation, asymmetric Strecker reaction, intramolecular Pd(0)-catalyzed allylic alkylation, photocycloadditions, azomethine ylide cycloaddition, dynamic kinetic resolution, enantioselective hydrogenation, and oxy-Michael reaction . However, few sigmatropic approaches have been reported, an exception being Sutherland’s Pd-catalyzed [3,3]-sigmatropic Overman rearrangement route …”

A Stereoselective Approach to 1,3‐Amino Alcohols Protected as Cyclic Carbamates: Kinetic vs. Thermodynamic Control

“…[2] Nevertheless, transferring chirality by substrate control is probably still the most common way to create stereocenters. In this context and as a part of a program directed at the synthesis of polyols [3] and hydroxy amino acids, [4] we were interested in the development of catalytic addition processes that could generate an initial chiral center that, in turn, could transfer its chirality to the neighboring atoms. Particularly, we focused our attention on the synthesis of 1,3-amino alcohols and γ-hydroxy α-amino acid substructures.…”