Trianglamines—Readily Prepared, Conformationally Flexible Inclusion‐Forming Chiral Hexamines

Abstract

Trianglamines, macrocyclic heteraphanes, were readily synthesised through a [3+3] cyclocondensation of (R,R)-1,2-diaminocyclohexane with terephthalaldehyde, followed by NaBH4 reduction and N-alkylation. The macrocyclic ring shows a remarkable ability to change its conformation, as a consequence of rotation about the C-N bonds or nitrogen inversion due to protonation or N-alkylation, as revealed by circular dichroism spectra, computational modelling and X-ray diffraction analysis. The flexible natures of the trianglamine macrocycles allow ready accommodation of a variety of guest molecules to form crystalline inclusion complexes of highly diversified interpenetrating structures.

Convenient Enantioselective Hydrosilylation of Ketones Catalyzed by Zinc‐Macrocyclic Oligoamine Complexes

“…This enantioselectivity is higher than that with the use of acyclic ligand 6 (ee 78%). Since trianglamine 2 can be conveniently prepared by a one-pot procedure from inexpensive tartrate salt of DACH and terephthalaldehyde, [31] the Zn complex of 2 is a good alternative to previously reported chiral catalysts.…”

“…Our previous study has shown that free ligand 2 possesses a large number of conformers belonging to families of similar structures. [31] These structures are defined by the signs and values of tor-…”

“…[31] Trianglamine 2 has already been used as a chiral shift reagent for NMR spectra, [35] as a chiral probe for anion recognition in ion-trap ESI-MS [36] and as a chiral ligand for copper-catalyzed enantioselective Henry reaction. [37] Ligands 2-6 feature the same secondary 1,2-di-A C H T U N G T R E N N U N G amine structure embedded in the cyclohexane ring.…”

“…For the present study we have selected trianglimine 1 [30] trianglamines 2, 3, [30,31] 4, [32,33] and rhombamine 5, [34] as well as N,N'-dibenzyl-DACH (6) as a reference ligand.…”

Samarium(III) nitrate-catalyzed one-pot synthesis of 42-membered N,S,O-containing cyclophanes

“…[1][2][3][4][5][6][7] A considerable drawback of this method is the formation of by-products arising from linear polycondensation or simultaneous [n+n]-cyclocondensation of the initial α,ω-bifunctional compounds. [8][9][10][11][12][13][14] The formation of by-products is minimised, as a rule, by using high dilution, 11,15,16 templates, [17][18][19][20][21][22] and catalytic reactions. [23][24][25][26][27] Cyclophanes containing benzene rings in the molecule have rigid cyclic skeletons, which is important for their complexation of metal ions 5 and organic molecules.…”