The typical crystal structures of a few representative α-aryl-α-hydroxyphosphonates

Abstract

The crystal structures of seven -aryl--hydroxyphosphonates synthesized by the Pudovik reaction of substituted benzaldehydes and dialkyl phosphites, namely dimethyl [(hydroxy)(phenyl)methyl]phosphonate, C 9 H 13 O 4 P, dimethyl [(3,4-dimethoxyphenyl)(hydroxy)methyl]phosphonate, C 11 H 17 O 6 P, dimethyl (1-hydroxy-1-phenylethyl)phosphonate, C 10 H 15 O 4 P, dimethyl [1-hydroxy-1-(4nitrophenyl)ethyl]phosphonate, C 10 H 14 NO 6 P, dibenzyl [hydroxy(2-nitrophenyl)methyl]phosphonate, C 21 H 20 NO 6 P, dibenzyl [(3-chlorophenyl)(hydroxy)methyl]phosphonate, C 21 H 20 ClO 4 P, and dibenzyl [hydroxy(4-methylphenyl)methyl]phosphonate, C 22 H 23 O 4 P, were studied to gain a better understanding of the organization in this type of molecule in the solid state. The crystals obtained for this series of compounds show a balance between C-OHÁ Á ÁO P chain-linked packing and the dimeric types of hydrogen-bond bridges of intermolecular pairs of such functions. The description is based on primary graph-set descriptors. Using graph-set descriptors one level deeper (i.e. secondary graph sets of the C-HÁ Á ÁO type) revealed a similarity in the graph-set descriptors, suggesting a fine interplay of substituent-and shape-dependent effects on strong-weak interactions. It seems that the formation of chains or dimers is governed not only by the presence of a tertiary C atom, but also by the nature and crowding of the ortho substituents of the -aryl group.

Kabachnik–Fields Reaction by Mechanochemistry: New Horizons from Old Methods

“…Such a difference can be ascribed to the larger steric demand of the isopropyl group in 11 with respect to the small ethyl groups in 1 hindering a closer approach in the former ring. A similar effect has been observed in a number of other cases − and is substantiated by the comparison with other diethyl and diisopropyl aminophosphonates forming 2 2 R­(10) rings extracted from the CSD and shown in Table .…”

Catalyst- and Solvent-Free Hydrophosphorylation of Ketones with Secondary Phosphine Oxides: Green Synthesis of Tertiary α-Hydroxyphosphine Oxides

“…calculated in the framework of the quantum theory 'Atoms in Molecules' 15a and the equations relating this electron density to energy of the intramolecular hydrogen bond. 15b At the same time, the intermolecular O−H•••O=P hydrogen bond bridges have been recognized 16 to form ring and chain motifs in the crystal structure of similar hydroxyphosphine oxides.…”

Optical Resolution of Dimethyl α-Hydroxy-Arylmethylphosphonates via Diastereomer Complex Formation Using Calcium Hydrogen O,O′-Dibenzoyl-(2R,3R)-Tartrate; X-Ray Analysis of the Complexes and Products

“…Another variant of the optical resolution involves acylation of hydroxyphosphonates with dibenzoyl-(R,R)-tartaric anhydride, that is followed by chromatographic separation, and decomposition of the covalent diastereomers [30]. In our previous article, we reported the synthesis of seven racemic dialkyl 1-hydroxy-arylmethylphosphonates and their structure determined by single crystal X-ray analysis [31]. It was observed that α-hydroxyphosphonates derived from substituted benzaldehydes are inclined to form chain-like associates, while dimers can be found in the crystal lattice of α-hydroxy-α-methylphosphonates formed from acetophenone derivatives [31].…”

“…In our previous article, we reported the synthesis of seven racemic dialkyl 1-hydroxy-arylmethylphosphonates and their structure determined by single crystal X-ray analysis [31]. It was observed that α-hydroxyphosphonates derived from substituted benzaldehydes are inclined to form chain-like associates, while dimers can be found in the crystal lattice of α-hydroxy-α-methylphosphonates formed from acetophenone derivatives [31]. Earlier, we were successful in the optical resolution of a series of cyclic phosphine oxides and phosphinates using the acidic calcium salt of O,O -dibenzoyl-(2R,3R)-tartaric acid as the resolving agent [32].…”