The Synthesis of Aldehydes From Grignard Reagents. Ii. Polymethylbenzaldehydes

Smith, Lee Irvin; Nichols, Joseph

doi:10.1021/jo01204a003

Cited by 66 publications

(10 citation statements)

References 13 publications

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“…Aromatic aldehydes are produced by the addition of Grignard reagents to ethyl N-phenylformimidate (115,234,301) and, as the reaction proceeds smoothly and ivithout great evolution of heat, the yields are superior to those obtained from the ethyl orthoformate synthesis of aldehydes (301).…”

Section: Reaction With Hydrazoic Acidmentioning

confidence: 99%

The Chemistry of Imidates.

Roger¹,

Neilson²

1961

Chem. Rev.

393

160

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Section: Reaction With Hydrazoic Acidmentioning

confidence: 99%

The Chemistry of Imidates.

Roger¹,

Neilson²

1961

Chem. Rev.

393

160

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“…8.0 to 8.6 kcal mol -1 in this temperature range, with a significant negative entropy of activation. This barrier is attributed to a rotational process of the ethyl groups since rotation about the Ar−Ar bond should display a significantly higher barrier . The rotational barrier is ca.…”

Section: Resultsmentioning

confidence: 99%

Conformation and Stereodynamics of Decaethylbiphenyl

1997

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The stereochemistry of decaethylbiphenyl (5) is analyzed. The potentially low-energy conformers of 5 were generated by formally linking two pentaethylphenyl subunits, and by assuming that no more that one syn interaction is present per ring. Molecular mechanics calculations (MM3 program) indicate that the forms “f”, “i”, “j”, and “m” represent the lowest energy conformations. As previously observed for decakis(bromomethyl)biphenyl, the “a” conformation (devoided of any syn arrangement of two neighboring ethyl groups) is destabilized by the mutual steric interactions of ortho ethyl groups at different rings. Decaethylbiphenyl (5) was synthesized by exhaustive ethylation of biphenyl. The compound exists in the crystal in three different conformations (“i”, “j”, and “m”). Low-temperature 13C NMR data show that the compound exists in CDCl2F at 149 K in two conformations in a 4:1 ratio, and the major conformer was assigned to the “m” form. Dynamic NMR data indicate that “m” undergoes ethyl rotation with a barrier of ΔG 176 ‡ = 8.2 ± 0.1 kcal mol-1. The interconversion graph of 5 was analyzed, and on the basis of the MM calculations and NMR data, it is concluded that the rotational process followed by NMR involves the stepwise rotation of the meta and para ethyl groups of “m”.

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“…1,2-Bis(2,5-dimethoxy-4-methylphenyl)cyclohexene (8). Aluminum chloride (10.5 g, 78.6 mmol) was added in portions to a stirred solution of 2,5-dimethoxytoluene (10.0 g, 65.8 mmol) and adipoyl chloride (5 mL, 34.4 mmol) in dichloromethane (100 mL) at 0 °C, under an argon atmosphere …”

Section: Methodsmentioning

confidence: 99%

Efficient Hydrogenation of Sterically Hindered Olefins with Borane−Methyl Sulfide Complex

1996

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Sterically hindered olefins are efficiently reduced to the corresponding alkanes by the borane−methyl sulfide (BMS) complex at room temperature (or below) in dichloromethane containing a mild one-electron oxidant (such as an aromatic cation radical) or by the passage of an anodic current. In an alternative procedure, the hydrogenation of the same (electron-rich) olefins with the BMS complex (in the absence of a one-electron oxidant) is also carried out in the presence of a strong Brønsted acid (such as HBF4). In the oxidative activation, olefin cation radicals are the first observable intermediates, and separate experiments (including transient electrochemistry) confirm the facile reduction of the olefin cation radical by borane to produce the corresponding alkane. The direct protonation of olefins produces carbocationic intermediates which are also efficiently reduced by borane to the corresponding alkanes. The intermediacy of both olefin cation radicals and carbocations in the hydrogenation procedure with borane is discussed.

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The Synthesis of Aldehydes From Grignard Reagents. Ii. Polymethylbenzaldehydes

Cited by 66 publications

References 13 publications

The Chemistry of Imidates.

The Chemistry of Imidates.

Conformation and Stereodynamics of Decaethylbiphenyl

Efficient Hydrogenation of Sterically Hindered Olefins with Borane−Methyl Sulfide Complex

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