A Simple Strategy for the Preparation of P‐Chirogenic Trost Ligands with Different Absolute Configurations

Abstract

P-chirogenic compounds are useful ligands and organocatalysts in asymmetric synthesis. However, the lack of preparative methods and their configurational instability have significantly hampered their development. Herein, we report a simple strategy for the preparation of enantiomerically pure P,C-chirogenic diphosphines. Amidation of the borane adducts of rac-phosphinobenzoic acids with enantiomerically pure trans-1,2-diaminocyclohexane afforded a 1:2:1 mixture of the diastereomers (C

LemPhos – New P-Chiral Phospholene Core Based Ligand

“…For example, a simple and elegant purification and separation of phosphine ligands was recently described by Du and Lu for the specific case of Trost-type ligands. 4…”

“…(–)-Nopadiene ( 5 ) was synthesized from nopol tosylate via an elimination reaction, according to literature procedures. 4 Phenylphosphine dichloride ( 12 ) was then subjected to reaction with the formed diene, giving a mixture of two P-epimers 13 observable in 31 P NMR spectroscopy (Scheme 3 ).…”

“…Due mostly to the applied reaction conditions (high pressure and temperature), the resulting product, which is mostly a class of phosphonium salt, easily undergoes epimerization of the phosphorus center resulting in the formation of a racemic mixture and the necessity to separate the enantiomers. The idea to apply a diene with a chiral pendant came first from Kagan and co-workers in a synthesis of PhellanPhos (4) and NopaPhos (7) (Scheme 1). 1 Nopol and its derivatives have been used several times as chiral pool sources in the construction of phosphine ligands.…”

P-Stereogenic Phosphorus Ligands in Asymmetric Catalysis

“…The C 2 -symmetric P-stereogenic bisphosphorus ligands reported from 2001 to 2023 are shown in Figure , in the order of their publication years. ,− ,,,− A tetraphosphine ligand L41 and a C 3 -symmetric triphosphine ligand MT-Siliphos are also included in this figure as exceptions. All of these ligands possess unique structural and electronic properties, arising from the two different substituents on the phosphorus atoms and the ligand backbones, and exhibit their characteristic reactivities and stereoselectivities in various transition-metal-catalyzed asymmetric reactions.…”