Additivity of Electrical Effects in Aromatic Electrophilic Substitutions as Determined by Desilylation Reactions

Benkeser, Robert A.; Hickner, Richard A.; Hoke, Donald I.; Thomas, Owen H.

doi:10.1021/ja01552a070

Cited by 36 publications

(13 citation statements)

References 4 publications

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“…In a crowded environment, substitution a t a methyl-bearing ring carbon should be favored because the methyl is moved out of the ring plane and strain is reduced. This steric compression has been demonstrated in desilylation reactions, where rates almost an order of magnitude above those predicted by additivity have been observed for protodesilylation and mercuridesilylation at SiMe, flanked by methyl groups (14,15). The well documented buttressing effect is now known to reduce the ring act~vating effect of methyl groups in crowded environnients.…”

Section: Resultsmentioning

confidence: 82%

Protonation of Polymethylphenols

Blackstock¹,

Richards²,

Wright³

1974

Can. J. Chem.

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The protonation of a series of polymethylphenols in fluorosulfonic acid at -50' has been studied. For those phenols with no substituent at C-4, protonaton occurs exclusively at that position. Isomeric ions were obtained for all phenols with a methyl substituent at C-4.4-Methylphenol and 2,4-dimethylphenol each gave three ions, one from 0-protonation and two from protonation a t C-2 and C-4, whereas 2,4-dimethylphenol, 2,3,4-, 2,4,5-, and 3,4,5-trimethylphenol, and 2,3,4,5-tetramethylphenol gave only the C-protonated species. These studies establish that although electronic factors are important, steric factors play a predominant role in determining the relative proportions of the various species.BLACKSTOCK, KEN~YETH E. RICHARDS et GRAEME J. WRIGHT. Can. J. Chem. [Traduit par le journal]

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Section: Resultsmentioning

confidence: 82%

Protonation of Polymethylphenols

Blackstock¹,

Richards²,

Wright³

1974

Can. J. Chem.

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“…It is known that the aryl-Si bond is easily cleaved by proton acids. 18,19 Fig. 1 shows the IR spectra of membranes of poly(DMOSDPA-co-TBDPA) and desilylated analogue [DSpoly(DMOSDPA-co-TBDPA)] in the feed ratio of 1 : 4.…”

Section: Fabrication and Desilylation Of Membranesmentioning

confidence: 99%

Enhancement of oxygen permeability by copolymerization of silyl group-containing diphenylacetylenes with tert-butyl group-containing diphenylacetylene and desilylation of copolymer membranes

2017

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“…Compound 1 was obtained by modification of a reported procedure [13,31]. Br 2 (8.64 ml, 0.168 mol) was added via a dropping funnel to a stirred solution of 2,6-isopropylaniline hydrochloride (35.9 g, 0.168 mol) in methanol (100 ml) and glacial acetic acid (50 ml).…”

Section: Synthesis Of Compound 4-bromo-26-diisopropylaniline (1)mentioning

confidence: 99%