Facile Enantioselective Ring‐Opening Reaction of meso Epoxides with Anilines Using (S)‐(–)‐BINOL‐Ti Complex as a Catalyst

Abstract

The catalytic enantioselective ring-opening reaction of mesostilbene oxide and cyclohexene oxide with anilines was catalyzed by (S)-(-)-BINOL-Ti complexes at ambient temperature to obtain β-amino alcohols in high yield (95 %) and enantioselectivity (ee, 78 %). The enantiomeric excess (ee) of the product was further improved to 98 % by a single recrystalli-

Dimeric & Polymeric Chiral Schiff Base Complexes and Supported BINOL Complexes as Potential Recyclable Catalysts in Asymmetric Kinetic Resolution and C–C Bond Formation Reactions

“…However, its use in epoxide ring opening reactions is limited and that too under homogeneous condition with no catalyst recycling data available [12][13][14][15][16]. In our laboratory [30] we used (S)-(-)-BINOL-Ti complexes 12-15 as recyclable catalysts in the enantioselective ring-opening reaction of meso stilbene oxide and cyclohexene oxide with anilines ( Fig. 6).…”

Enantioselective desymmetrization of meso‐epoxides with anilines catalyzed by polymeric and monomeric Ti(IV) salen complexes

“…The remaining solid was further washed with hexane (10 ml), dried under reduced pressure at 508C for 122 h, and was used as recovered catalyst 1. (1S,2S)-1,2-Diphenyl-2-(4-methoxy-phenylamino)-ethanol 19,20 . The title compound was isolated by column chromatography (n-hexane/AcOEt 90/10) as a yellow solid.…”

“…Melting point: 98-1028C. 19 ee 95% on HPLC (Chiralpak OD column) mobile phase, 85/15 n-hexane/iPrOH; flow rate 1 ml/min, k 5 247 nm, t R (1S,2S) 5 18.68 min, t R (1R,2R) 5 22.52 min. LC-MS, m/z 661 [2M (2S,3S)-2-N-Phenylamino-3-butanol 20,24 .…”

“…The title compound was isolated by column chromatography (nhexane/AcOEt 90/10) as an oil. ee 19% on HPLC (Chiralpak OD column) mobile phase, 97.5/2.5 n-hexane/iPrOH; flow rate 1 ml/min, k 5 247 nm, t R (2S,3S) (1S,2S)-2-(Phenylamino)-cyclohexane-1-ol 19,20 . The title compound was isolated by column chromatography (n-hexane/AcOEt 90/10) as a white solid.…”

Chiral recyclable dimeric and polymeric Cr(III) salen complexes catalyzed aminolytic kinetic resolution of trans‐aromatic epoxides under microwave irradiation

“…10,11 Though these methods gave products with high enantioselectivity for syn-b-amino alcohols, very few methods favored the formation of optically pure anti-b-amino alcohols. [12][13][14][15][16][17][18][19] In this direction, aminolytic kinetic resolution (AKR) of racemic 1,2-disubstituted epoxides with amines as nucleophiles is an attractive method for the synthesis of optically pure anti-b-amino alcohols with high diastereoselectivity. [20][21][22] Bartoli et al for the first time has reported the ring opening of transand meso-epoxides with anilines for the synthesis of anti/ syn-b-amino alcohols using chiral monomeric Cr(III) salen as a catalyst, but separation and recycling of the catalyst is not feasible under homogeneous catalytic system.…”