(Nonracemic) thiols and Zn II . Structural and catalytic aspects of some natural and non-natural zinc thiolates

Abstract

The catalytically active Zn II ion of the enzyme horse liver alcohol dehydrogenase (HLADH) is well known to be coordinated to two thiolates and an imidazole. Attempts to prepare models of this catalytically active Zn II complex are complicated by the great tendency of Zn II thiolates to form oligomeric structures. Some approaches to monomeric structures are described. Work on this problem has led to spin-offs in the form of the use of β β-aminothiols as ligands in the addition of diethylzinc to aldehydes. Monomeric zinc complexes are believed to be the active intermediates in this reaction. Excellent control over the enantioselectivity can be obtained. Methods developed in recent years for the synthesis of a variety of functionalized chiral nonracemic thiols open the way to the development of a catalytic chemistry of thiols in general and Zn II thiolates in particular.

Syntheses, characterization, density functional theory calculations, and activity of tridentate SNS zinc pincer complexes

“…Our calculations show that a pseudo-tetrahedral geometry is preferred for a d 10 zinc system with a ligand precursor set that is analogous to that found in complexes 1-3…”

“…The nitrogen and sulfur donor atoms are provided by histidine and cysteine residues of a single polypeptide chain [5]. Several structural models for LADH have been reported with the same donor atoms as the metalloenzyme [6][7][8][9][10][11][12][13]. In some cases, reactivity data was not reported [14].…”

“…Overall, the relative stabilities of the pseudo-tetrahedral and pseudo-square planar systems are the same for this coordination environment whether the ligand set is a single tridentate SNS system or is broken into three separate units. The preference of a d 10 Zn center to attain a tetrahedral local environment trumps any stabilization gained by removal of constraints within the ligand set.…”

Direct Electrochemical Synthesis of Aluminium(III) Thiolates and their Coordination Compounds

“…In the world today, this technique has become progressively dominant and attracted a great deal of attention because of their synthetic utility in organic [1][2] , inorganic 3 , green, nanochemistry 4 , metal deposition, chemical and pharmaceutical industries 5 , neurosciences etc. Metal sulphur complexes have become the subject of great interest because of their importance in material precursors, metalloenzymes and catalyts 6 .…”

Synthesis and application of chiral β‐amino disulfides as ligands for the enantioselective addition of diethylzinc to aldehydes

“…25 In the last few years, a significant improvement in enantioselectivity has been observed by the use of amino sulfur or selenium moieties as catalysts for the enantioselective addition of diethylzinc to aldehydes. [26][27][28][29][30][31][32] Sulfur containing ligands 33 like b-amino thiols and b-amino disulfides derivatives from ephedrine, [34][35][36] norephedrine, [37][38][39] (S)-proline, [40][41][42] (S)-phenylglycine, 43 (S)-valine, 44,45 (R)-cysteine, 5,46-50 (R)-cystine, 51 and others [52][53][54][55][56][57][58] have gained more and more interest as catalysts in this stereoselective reaction. In a similar way, chiral amino diselenides have been efficiently used as catalysts for this addition, [28][29][30][31][32] but due to the most difficult accessibility of these compounds, only a few number of reports can be found in literature.…”