Asymmetric Ring Opening of meso‐Epoxides Catalyzed by the Chiral Phosphine Oxide BINAPO.

Abstract

Enantioselective syntheses O 0031Asymmetric Ring Opening of meso-Epoxides Catalyzed by the Chiral Phosphine Oxide BINAPO. -Bis(phosphine oxide) (S)-BINAPO is an effective catalyst for the synthesis of chlorohydrins from meso-epoxides and tetrachlorosilane. Since the presence of iPr2NEt in the reaction of stilbene oxide dramatically enhances the enantioselectivity, these conditions are also applied to the other epoxides (I) and (III). -(TOKUOKA, E.; KOTANI, S.; MATSUNAGA, H.; ISHIZUKA, T.; HASHIMOTO, S.; NAKAJIMA*, M.; Tetrahedron: Asymmetry 16 (2005) 14, 2391-2392; Fac. Med. Pharm. Sci., Kumamoto Univ., Oehon, Kumamoto 862, Japan; Eng.) -Klein 50-032

Evaluation of bifunctional chiral phosphine oxide catalysts for the asymmetric hydrosilylation of ketimines

“…The earliest report of the use of a P-chiral phosphine oxide detailed the application as a ligand for asymmetric transfer hydrogenation of ketones, [6] and subsequent studies have shown applicability in a number of synthetic applications, including Diels-Alder reactions, [7] enantioselective allylation of -hydrazono esters, [8] desymmetrisation of diaryl mesoepoxides, [9] reductive aldol condensations, [10] and reductive cyclisation of N-acylated-amino enones. [11] The latter two transformations make use of trichlorosilane as a reductant, a reagent known for susceptibility for activation by Lewis base catalysts, a majority of which are amide based.…”

Straightforward Synthesis of Bifunctional Phosphorus Phenols via Phosphination of In Situ Generated o-Quinone Methides

“…In particular, aside from the well-known triphenylphosphine oxide, plenty of novel phosphine oxides have been designed and synthesized as useful molecules for both industry and academia. For example, the chiral phosphine oxide compound A (BINAPO) [ 12 ] and the bisoxazoline phosphorus ligand B [ 13 ] have been employed as a catalyst or ligand to catalyze versatile asymmetric reactions; the phosphorus chromones C is a progesterone receptor antagonist [ 14 ]; compound D is known as a preeminent flame retardant [ 15 ] ( Figure 1 ).…”

Enantioselective addition-alkylation reactions via bisguanidinium silicate ion pair catalysis

“…Epoxides play an important role in organic synthesis as a variety of nucleophiles can be employed in the ring opening reactions. Denmark et al 68 Nakajima's group reported that also chiral phosphine oxide (S)-BINAPO 71 can catalyze the enantioselective ring opening of meso-epoxides in the presence of tetrachlorosilane, affording the corresponding chlorohydrins in high enantioselectivities (up to 90% ee) (Figure 1.30b).…”