Multinuclear enantiopure titanium self‐assembly complexes—synthesis, characterization and application to organic synthesis

Abstract

Hexa-and nonanuclear titanium complexes were obtained by self-assembly of titanium(IV)-tertbutoxide and D-mandelic acid. Suitable single crystals of these complexes were characterized by X-ray structure analysis. When used with these complexes, aldol adducts were isolated with a high degree of regioselectivity in direct aldol additions of aromatic and aliphatic aldehydes to functionalized unsymmetrical ketones. High syn-diastereoselectivities were obtained in aldol additions of enolizable aldehydes with hydroxyacetone and methoxyacetone.

Titanium‐Oxo Clusters with Bi‐ and Tridentate Organic Ligands: Gradual Evolution of the Structures from Small to Big

“…Clusters containing both carboxylato and phosphonato ligands will be discussed in Section 3, for the reasons given there. TOC structures with hydroxycarboxylato ligands (such as mandelate, [4] salicylate, [5] 1‐hydroxy‐2‐naphthoate, [5c] 2,5‐dihydroxybenzoate [6] or citrate [7] ) will not be treated. The OH group is always deprotonated and therefore hydroxycarboxylato ligands not only have a variety of coordination possibilities [8] but also a stronger and different structure‐directing role than simple carboxylato ligands; their coordination requires a specific orientation of the coordination polyhedra of neighboring metals.…”

1D CoII and NiII Chiral Polymers That Exhibit Ferromagnetic Interactions

“…Scheme 1. Reported coordination modes for mandelic acid: A, [24,25] B, [26] C, [25,27,28] D, [29][30][31] E, [32][33][34] and F. [35] In this paper, we report the result of a synthetic procedure with different metal ions (Mn II …”

Total Syntheses of Carbohydrates: Organocatalyzed Aldol Additions of Dihydroxyacetone

“…In these investigations the author used strongly basic anion-exchange resins. [12] For direct titaniumcatalyzed aldol additions of enolizable aldehydes to hydroxyacetone see also reference [13].…”