Topic
Steric effects
About: Steric effects is a research topic. Over the lifetime, 16112 publications have been published within this topic receiving 319615 citations. The topic is also known as: steric hindrance.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: The X-ray crystal packing analyses of the sterically encumbered halogen-substituted benzene carboxylic acids 1-4 reveal a novel and unprecedented crystal packing in that the association of the carboxyl groups through O-H...O bonds results in the generation of a helix along the 41-screw axis.
Abstract: The X-ray crystal packing analyses of the sterically encumbered halogen-substituted benzene carboxylic acids 1−4 reveal a novel and unprecedented crystal packing in that the association of the carboxyl groups through O−H···O bonds results in the generation of a helix along the 41-screw axis. Such an organization of the acids is shown convincingly to be a result of the close packing, which exploits the weaker X···X and C−H···X interactions in conjunction with the stronger O−H···O hydrogen bonds. In contrast, the chloro- and bromo-substituted durene carboxylic acids 6 and 7 exhibit a pattern that is akin to tape/ribbon involving the centrosymmetric-dimer motif and X···X short intermolecular interactions. The structural investigations demonstrate the ability of the weaker interactions in modifying the supposedly “robust” centrosymmetric-dimer motif of the carboxyl groups in a decisive manner.
109 citations
••
TL;DR: In this article, the role of steric bulk and π electron release within the ERn substituent in generating tractable borylene complexes has been probed, as has the nature of the counterion.
108 citations
••
TL;DR: Application of these phosphine ligands in palladium-catalyzed C-N bond forming reactions revealed the crucial roles of the steric bulk of the substituents on the phosphorus atom governing the catalytic activity.
Abstract: A series of 2-dialkylphosphino-2'-alkoxy-1,1'-binaphthyl ligands (6a-c and 8a-c) have been prepared conveniently by a lithium-initiated ring-opening reaction of dinaphthofuran, followed by selective phosphorylation. These compounds displayed a remarkable air and moisture stability, both in solid form and in solution. Application of these phosphine ligands in palladium-catalyzed C-N bond forming reactions revealed the crucial roles of the steric bulk of the substituents on the phosphorus atom governing the catalytic activity. Specifically, 2-di-tert-butylphosphino-2'-isopropoxy-1,1'-binaphthyl (8b) proved to be the most effective for the aminations of aryl halides with primary amines, while the less bulky 2-dicyclohexyl-2'-methoxy-1,1'-binaphthyl (6a) was more effective for the aminations with secondary amines. The steric and electronic effects of the ligands were analyzed to account for these observations.
108 citations
••
TL;DR: A generally highly efficient and broadly applicable synthesis of carboxymethyl ketones from readily available carboxylic acids and terminal alkynes is developed under exceptionally mild reaction conditions.
Abstract: Steric Bulk or Conformation Control? Optimization of P,N-bidentate ligands reveals the importance of conformation control in the development of highly efficient intermolecular trapping of reactive α-oxo gold carbene intermediates. While a pendant piperidine ring offers suitable steric bulk, fixing its conformation to provide better shielding to the highly electrophilic carbene center turned out to be crucial for the excellent reaction efficiency. A generally highly efficient and broadly applicable synthesis of carboxymethyl ketones from readily available carboxylic acids and terminal alkynes is developed under exceptionally mild reaction conditions.
108 citations
••
TL;DR: In this article, it was shown that with a suitably bulky bidentate ligand, three-coordinate, high-spin alkyl complexes of iron(II) are stable.
108 citations