ChemInform Abstract: SYNTHESIS OF 2‐(S)‐BENZYLOXIRANE

Sanghvi, Yogesh S.; Dabral, V.; Rao, A. S.

doi:10.1002/chin.198329156

Cited by 2 publications

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“…The route selected for the preparation of 10 and 11 is outlined in Scheme . The conversion of 21 to 32 was quickly determined to be problematic because of competitive formation of the dibenzylidene derivative under conventional aldol condensation conditions 40a. In order to curtail the formation of this product, the aldol reaction mixture was treated with methanesulfonyl chloride 5 s after introduction of the benzaldehyde 40b.…”

Section: Resultsmentioning

confidence: 99%

“…The conversion of 21 to 32 was quickly determined to be problematic because of competitive formation of the dibenzylidene derivative under conventional aldol condensation conditions 40a. In order to curtail the formation of this product, the aldol reaction mixture was treated with methanesulfonyl chloride 5 s after introduction of the benzaldehyde 40b. The subsequent addition of triethylamine was followed either by a reflux period of 1 h or overnight stirring at room temperature.…”

Section: Resultsmentioning

confidence: 99%

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π-Facial Diastereoselection in the 1,2-Addition of Allylmetal Reagents to 2-Methoxycyclohexanone and Tetrahydrofuranspiro-(2-cyclohexanone)

Paquette

Lobben

1996

J. Am. Chem. Soc.

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The stereochemical course of the 1,2-addition of several allylmetal reagents and of the Normant Grignard [ClMgO(CH2)3MgCl] to 2-methoxycyclohexanone and tetrahydrofuranspiro-(2-cyclohexanone) has been determined. In four of the six substrates examined, a 4-tert-butyl group is present to serve as a conformational anchor. The neighboring methoxyl substituent is shown to be capable of engaging effectively in chelation, although special circumstances can dictate otherwise. Experiments involving the allylindium reagent as the nucleophile in aqueous solution reveal that the presence of water does not inhibit the operation of chelation control, which often exceeds that attainable with the corresponding magnesium, cerium, and chromium reagents in anhydrous media by significant margins. The extent to which cooperation between the α-oxygen atom and control of π-facial nucleophilic attack reaches a maximum (>97:3) is when the system is conformationally rigid and the 2-methoxy and 4-tert-butyl groups are both oriented equatorially. As the steric bulk about the oxygen is increased, the ability of indium to anchor onto the heteroatom is significantly lessened. The results of competition experiments are detailed. The prospects for useful synthetic applications of indium catalysis in water or water/THF mixtures appear to be very promising.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

π-Facial Diastereoselection in the 1,2-Addition of Allylmetal Reagents to 2-Methoxycyclohexanone and Tetrahydrofuranspiro-(2-cyclohexanone)

Paquette

Lobben

1996

J. Am. Chem. Soc.

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“…Crystals of Cs 7 (H 4 PO 4 )(H 2 PO 4 ) 8 were grown for single-crystal X-ray diffraction from the powder precursor samples using a high-temperature deliquescence and crystallization procedure . Approximately 1 g of the powder sample of CDP and CsH 5 (PO 4 ) 2 was heated to 102 °C in a tube furnace.…”

Section: Methodsmentioning

confidence: 99%

Structure and Properties of Cs₇(H₄PO₄)(H₂PO₄)₈: A New Superprotonic Solid Acid Featuring the Unusual Polycation (H₄PO₄)⁺

et al. 2020

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We report the discovery of a new superprotonic compound, Cs 7 (H 4 PO 4 )(H 2 PO 4 ) 8 , or CPP, which forms at elevated temperatures from the reaction of CsH 2 PO 4 and CsH 5 (PO 4 ) 2 . The structure, solved using high-temperature single-crystal X-ray diffraction and confirmed by high-temperature 31 P NMR spectroscopy, crystallizes in space group Pm3̅ n and has a lattice constant of 20.1994(9) Å at 130 °C. The unit cell resembles a 4 × 4 × 4 superstructure of superprotonic CsH 2 PO 4 , but features an extraordinary chemical moiety, rotationally disordered H 4 PO 4 + cations, which periodically occupy one of every eight cation sites. The influence of this remarkable cation on the structure, thermodynamics, and proton transport properties of the CPP phase is discussed. Notably, CPP forms at a temperature of 90 °C, much lower than the superprotonic transition temperature of 228 °C of CsH 2 PO 4 , and the compound does not appear to have an ordered, low-temperature form. Under nominally dry conditions, the material is stable against dehydration to ∼151 °C, and this results in a particularly wide region of stability of a superprotonic material in the absence of active humidification. The conductivity of Cs 7 (H 4 PO 4 )(H 2 PO 4 ) 8 is moderate, 5.8 × 10 −4 S cm −1 at 140 °C, but appears nevertheless facilitated by polyanion (H 2 PO 4 − ) group reorientation.

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ChemInform Abstract: SYNTHESIS OF 2‐(S)‐BENZYLOXIRANE

Abstract: Nach bekanntem Verfahren wird über den aus D‐Mannit zugänglichen Aldehyd (I) das Triol (II) und daraus das Triacetat (III) hergestellt, dessen benzylische OH‐Gruppe durch Hydrieren (H2, Pd/C) abgespalten wird.

Cited by 2 publications

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π-Facial Diastereoselection in the 1,2-Addition of Allylmetal Reagents to 2-Methoxycyclohexanone and Tetrahydrofuranspiro-(2-cyclohexanone)

π-Facial Diastereoselection in the 1,2-Addition of Allylmetal Reagents to 2-Methoxycyclohexanone and Tetrahydrofuranspiro-(2-cyclohexanone)

Structure and Properties of Cs₇(H₄PO₄)(H₂PO₄)₈: A New Superprotonic Solid Acid Featuring the Unusual Polycation (H₄PO₄)⁺

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ChemInform Abstract: SYNTHESIS OF 2‐(S)‐BENZYLOXIRANE

Abstract: Nach bekanntem Verfahren wird über den aus D‐Mannit zugänglichen Aldehyd (I) das Triol (II) und daraus das Triacetat (III) hergestellt, dessen benzylische OH‐Gruppe durch Hydrieren (H2, Pd/C) abgespalten wird.

Cited by 2 publications

References 0 publications

π-Facial Diastereoselection in the 1,2-Addition of Allylmetal Reagents to 2-Methoxycyclohexanone and Tetrahydrofuranspiro-(2-cyclohexanone)

π-Facial Diastereoselection in the 1,2-Addition of Allylmetal Reagents to 2-Methoxycyclohexanone and Tetrahydrofuranspiro-(2-cyclohexanone)

Structure and Properties of Cs7(H4PO4)(H2PO4)8: A New Superprotonic Solid Acid Featuring the Unusual Polycation (H4PO4)+

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Structure and Properties of Cs₇(H₄PO₄)(H₂PO₄)₈: A New Superprotonic Solid Acid Featuring the Unusual Polycation (H₄PO₄)⁺