Asymmetric ring opening of meso-epoxides catalyzed by the chiral phosphine oxide BINAPO

Tokuoka, Eisuke; Kotani, Shunsuke; Matsunaga, Hirofumi; Ishizuka, Tadao; Hashimoto, Shunichi; Nakajima, Makoto

doi:10.1016/j.tetasy.2005.06.021

Cited by 84 publications

(33 citation statements)

References 22 publications

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“…[34] The use of the chiral phosphoramide (R)-1 in combination with SiCl 4 led to the enantioselective synthesis of chlorohydrins, Scheme 12. Following our initial report, other groups described the use of N-oxides, [35,36] phosphines, [37] and phosphine oxides [38] (Scheme 13). As part of an ongoing program in these laboratories on Lewis base-catalyzed reactions of silicon tetrachloride, we sought to investigate a number of preparative and mechanistic features of the epoxide ring opening reaction to garner a clearer understanding of the role of each of the reaction components and potentially the origin of enantioselectivity.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Ring Opening of Epoxides with Silicon Tetrachloride in the Presence of a Chiral Lewis Base: Mechanism Studies

et al. 2007

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Abstract:The enantioselective ring opening of mesoepoxides (from both cyclic and acyclic olefins) with silicon tetrachloride under catalysis by chiral phosphoramides affords enantiomerically enriched chlorohydrins in excellent yields. Experiments designed to elucidate the mechanistic foundation and origins of enantioselectivity are described. From studies on the loading and stoichiometry of the reagent (SiCl 4 ) and the catalyst [(R)-1] it was established that only one chloride per SiCl 4 is delivered and that the nature of reactive species does not change over the course of the reaction. Kinetic studies together with asymmetric amplification experiments have suggested that more than one catalyst molecule may be bound to SiCl 4 in the stereochemistry-determining transition structure.

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Section: Introductionmentioning

confidence: 99%

Enantioselective Ring Opening of Epoxides with Silicon Tetrachloride in the Presence of a Chiral Lewis Base: Mechanism Studies

et al. 2007

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“…[18] In conclusion, the biheteroaromatic diphosphine oxide tetraMe-BITIOPO easily available in both the enantiomerically pure forms in large amounts, being the precursor of the industrially produced tetra-Me-BITIOP, [19] was shown to be a really chemically and stereochemically efficient catalyst for the reaction of trichlorosilyl compounds. In particular the allylation of aldehydes afforded the products in very high yields and ees up to 95%, providing novel insights in the design and synthesis of new chiral Lewis bases as effcient organocatalysts.…”

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confidence: 99%

Novel Chiral Biheteroaromatic Diphosphine Oxides for Lewis Base Activation of Lewis Acids in Enantioselective Allylation and Epoxide Opening

2008

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Enantiomerically pure biheteroaromatic diphosphine oxides were synthesised and tested as organocatalysts in two different reactions involving trichlorosilyl compounds. The allylation of aldehydes with allyl(trichloro)silane afforded homoallylic alcohols in fair to good yields and up to 95% ee. Preliminary experiments showed that this new class of metal-free catalysts was able also to promote the stilbene oxide opening by addition of tetrachlorosilane with enantioselectivity higher than 80%. The interesting results in terms of chemical and stereochemical efficiency open the way to further studies towards the development of new chiral heteroaromatic Lewis bases as efficient metal-free catalysts.

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“…[6] Given the availability of the reviews in these areas, [3] the focus of this article is on several different families of chiral pyridine N-oxide catalysts developed for the enantioselective ring opening of epoxides with silicon tetrachloride, a reaction first studied by A C H T U N G T R E N N U N G Denmark and co-workers with a chiral phosphoramide catalyst (Scheme 1). [7][8][9] This reaction creates a new carbonchlorine bond enantioselectively. The mechanism is thought to proceed via a cationic silicon/Lewis base (e.g., phosphoramide) species that activates an epoxide towards chloride addition (Scheme 1B).…”

Section: Introductionmentioning

confidence: 99%

Helical Chiral Pyridine N‐Oxides: A New Family of Asymmetric Catalysts

Chen

Takenaka

2009

Chemistry A European J

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Optically active chiral alkyl chlorides are valuable compounds because of their bioactivity and versatile synthetic utility. Accordingly, the ring opening of epoxides with a chloride nucleophile stands as an important goal in asymmetric catalysis. We describe herein recent advances in the design and development of chiral pyridine N-oxide catalysts for the enantioselective synthesis of chlorohydrins.

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Asymmetric ring opening of meso-epoxides catalyzed by the chiral phosphine oxide BINAPO

Cited by 84 publications

References 22 publications

Enantioselective Ring Opening of Epoxides with Silicon Tetrachloride in the Presence of a Chiral Lewis Base: Mechanism Studies

Enantioselective Ring Opening of Epoxides with Silicon Tetrachloride in the Presence of a Chiral Lewis Base: Mechanism Studies

Novel Chiral Biheteroaromatic Diphosphine Oxides for Lewis Base Activation of Lewis Acids in Enantioselective Allylation and Epoxide Opening

Helical Chiral Pyridine N‐Oxides: A New Family of Asymmetric Catalysts

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