Atropodiastereoselective Cleavage of Configurationally Unstable Biaryl Lactones with Amino Acid Esters

Abstract

An improved procedure for the stereoselective synthesis of axially chiral biaryl systems is described, by atroposelective ring cleavage of configurationally unstable lactone-bridged biaryls with amino acid esters as inexpensive and efficient chiral N-nucleophiles. Starting with configurationally unstable lactones of type 2, which are readily accessible by intramolecular Heck reaction of the respective bromo esters 1, the atroposelective ring cleavage succeeds by using a broad variety of amino acid esters of type 5, leading to configuratively stable axially chiral biaryl amides 3 in good chemical yields and excellent diastereomeric ratios of up to Ͼ 99.5:0.5.

Biocatalytic Routes to Enantiomerically Enriched Dibenz[c,e]azepines

“…The conformers obtained are the result of thermodynamic equilibration (86:14 major/minor at 298 K) . As the conformers of 1 a can interconvert rapidly, it is possible the enzymes can carry out a dynamic process in which a single conformer of the imine is converted into the major product conformer (Scheme , Path A) . However, we cannot rule out whether the enzymes can reduce the imine conformer that would lead to the minor conformer (Scheme , Path B).…”

Synthesis and crystallographic structure of nickel(0) carbonyl complex with Bitianp, an atropoisomeric diphosphine

“…Bidentate diphosphine have played a key role in several catalytic processes and have proved to be among the most active chiral ligands for stereoselective applications [1][2][3][4][5]. Atropoisomeric diphosphines [6][7][8][9], in particular, represent a class of phosphorus ligands that have been established as being extremely efficient in the asymmetric hydrogenation of a wide range of substrates, particularly aryl and heteroaryl ketones [10][11][12][13][14][15][16][17]. Whereas, Ni(0) complexes of atropoisomeric diphosphines are known for stereo-selectively catalysis of αarylation [18][19][20][21].…”

Synthesis of (−)‐Viriditoxin: A 6,6′‐Binaphthopyran‐2‐one that Targets the Bacterial Cell Division Protein FtsZ

“…[27, 28] Subsequent recent examples for asymmetric biaryl construction often employ auxillary- and catalyst-controlled oxidative homo-coupling [29–31] and cross-coupling reactions. [32–35] In two complementary approaches, atropselectivity can also be realized by the asymmetric de novo assembly of aromatic rings in cycloadditions [36–41] and by dynamic kinetic resolution polycyclic lactones through aminolysis [42] or reduction. [43] or reduction.…”