Enantiomerization of Axially Chiral Biphenyls: Polarizable MD Simulations in Water and Butylmethylether

Abstract

In this study, we investigate the influence of chiral and achiral cations on the enantiomerization of biphenylic anions in n-butylmethylether and water. In addition to the impact of the cations and solvent molecules on the free energy profile of rotation, we also explore if chirality transfer between a chiral cation and the biphenylic anion is possible, i.e., if pairing with a chiral cation can energetically favour one conformer of the anion via diastereomeric complex formation. The quantum-mechanical calculations are accompanied by polarizable MD simulations using umbrella sampling to study the impact of solvents of different polarity in more detail. We also discuss how accurate polarizable force fields for biphenylic anions can be constructed from quantum-mechanical reference data.

Structural and conformational analysis of a biaryl phosphine integrating a calix[4]arene cavity. Can the phosphorus atom behave as an introverted donor?

“…Thus the stereoisomer found in the solid should merely be regarded as an out-conformer. only occurs for rotational barriers above 30 kcal mol −1 . 13 It should also be mentioned here that B was not the most stable in-conformer found in this study ( vide infra ).…”

The Physical Chemistry and Chemical Physics (PCCP) Section of the International Journal of Molecular Sciences in Its Publications: The First 300 Thematic Articles in the First 3 Years

“…This direction is represented by 39 articles [ 28 , 35 , 129 , 134 , 136 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 , 220 , 221 , 222 , 223 ]. Their distribution, according to the above types, is presented in Table 7 .…”

“…This expectation is fully consistent with reality, since most of the articles in this direction (31 of 39) are precisely the articles in groups ( b ) and ( c ). Moreover, the articles in group ( b ) constitute the largest part of all the articles related to Thematic Area 6; these include [ 35 , 134 , 190 , 191 , 196 , 197 , 198 , 201 , 203 , 205 , 206 , 207 , 211 , 216 , 217 , 218 , 219 ]. For formal reasons, the list of just cited references can also include the original article [ 208 ] and the review [ 220 ] devoted to graphene and fullerenes, since they all contain carbon–carbon bonds, and, according to the IUPAC standards, they should be classified as organic compounds (although, in general, this means that all chemical compounds consisting of atoms of only one chemical element are traditionally considered objects of inorganic chemistry).…”

Exploring Free Energy Profiles of Enantioselective Organocatalytic Aldol Reactions under Full Solvent Influence

“…Reactions already studied in literature include the Wittig reaction [ 35 ], organocatalytic addition to , -unsaturated ketones [ 36 ], chiral catalyzed ketimine-ene reactions [ 37 ], weak acid dissociation [ 38 ], organocatalytic S 2 reactions [ 39 , 40 ], the catalytic vinylogous Henry reaction [ 41 ], base-catalyzed Knoevenagel condensations [ 42 , 43 ], the Meyer–Schuster rearrangement [ 44 ], enantiomerization of axially chiral biphenyls [ 45 ], and also proline-catalyzed reactions [ 46 , 47 , 48 ]. While some of these studies obtained their results by using static quantum chemical calculations and frequently described solvent influence via continuum solvation models [ 37 , 39 , 40 , 42 , 43 , 44 , 49 , 50 , 51 ], others were based on molecular dynamics simulations and often used tools such as metadynamics [ 35 , 38 , 43 , 46 , 52 , 53 , 54 ] and umbrella sampling [ 45 ] to investigate the potential energy surfaces of the reactions. The metadynamics approach, originally proposed by Parrinello et al [ 55 ], reveals the free energy surface of one or more reaction coordinates by applying an adaptive bias potential.…”