Consecutive dynamic resolutions of phosphine oxides

Abstract

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The resolution of acyclic P‐stereogenic phosphine oxides via the formation of diastereomeric complexes: A case study on ethyl‐(2‐methylphenyl)‐phenylphosphine oxide

“…In the study of the resolving agents, the stirring of the solid diastereomers in a given solvent mixture was the purification method used. 21,44,78,79 Besides the purification of diastereomers used earlier ( Table 2, entry 2), the repeated resolution according to the half equivalent or the equivalent method, or the recrystallization of the enantiomeric mixtures was also considered as an option.…”

“…[28][29][30][31][32][33] Moreover, the costs of such separations may be decreased by using a supercritical fluid as the mobile phase, which complements the time efficiency of chromatographic separations with cost efficiency. [40][41][42][43][44] However, many enantioseparation methods developed for chiral phosphine oxides comprise classical resolutions. Many methods based on the formation of covalent diastereomers, diastereomeric salts, or diastereomeric complexes were elaborated for P-chiral phosphine oxides.…”

“…3,4,[35][36][37][38][39] In a few cases, dynamic resolutions were also developed. 44,54 Our research group found that TADDOL derivatives and the Ca 2+ salts of tartaric acid derivatives were suitable resolving agents to separate the enantiomers of several 5-and 6-membered P-heterocyclic phosphine oxides having various substitution patterns. In this manner, the total amount of the racemic starting material may be converted into a single enantiomer.…”

“…In this manner, the total amount of the racemic starting material may be converted into a single enantiomer. [40][41][42][43][44] However, many enantioseparation methods developed for chiral phosphine oxides comprise classical resolutions. Although a number of methods were elaborated over the decades, most of these resolutions were individual examples, and a generally applicable resolving agent for a wide variety of phosphine oxides is still to be found.…”

Double Asymmetric Induction During the Addition of (RP)‐Menthyl Phenyl Phosphine Oxide to Chiral Aldimines

“…Montchamp's group obtained P,C‐stereogenic α‐hydroxyl phosphinates in 94% (de) by means of the asymmetric induction of chiral phosphorus in Wittig rearrangement . Recently, Couzijn and we separately reported the addition of the secondary phosphine oxides to aldehydes to afford α‐hydroxyl tertiary phosphine oxides in excellent yield and diastereoselectivity …”