Acidities of carbon acids. VII. Conjugation and strain in some cyclopropyl anions

Bordwell, F. G.; Vanier, Noel R.; Matthews, Walter S.; Hendrickson, James B.; Skipper, Paul L.

doi:10.1021/ja00857a033

Cited by 88 publications

(34 citation statements)

References 3 publications

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“…A most interesting feature relates, however, to the behavior of the σ adduct 4 H − of 6‐trifluoromethylsulfonyl‐4‐nitrobenzofuroxan. Consistent with previous findings in the benzene series that the SO 2 CF 3 group exerts in many instances a greater electron‐withdrawing effect than a NO 2 group,44–46 this compound affords σ adducts which are more stable than the related DNBF adducts 47–49. On this ground, the measurement of a highest E ° value for 4 H − than for 1 H − fits well the trend discussed above.…”

Section: Discussionsupporting

confidence: 90%

Electrochemical Oxidation ofσ-Complex-Type Intermediates in Aromatic Nucleophilic Substitutions

et al. 2001

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A series of sigma-adducts (1H-...7H-) derived from the addition of 2-nitropropenide ion to various nitrobenzofuroxans and nitrobenzofurazans have been oxidized electrochemically. The results show that the rearomatization of the carbocyclic ring of these adducts as well as that of a few additional 4,6-dinitrobenzofuroxan adducts (8 H- a-c) is associated with much higher oxidation potentials than found for the same process in the dinitro- and trinitrobenzene series. Especially high Eo values are measured for the oxidation of the 2-nitropropenide 4,6-dinitro- and 4-nitro-6-trifluoromethylsulfonylbenzofuroxan adducts 1H- and 4H- in acetonitrile: E (1H-)= 1.15 V versus SCE; Eo(4H-)=1.33V versus SCE. These values fit well with the available evidence that the chemical oxidation of these adducts requires the use of very strong oxidizing agents to proceed efficiently. The mechanism for the oxidation process has been established. It is shown to involve transfer of two electrons and liberation of one proton per sigma-complex precursor with no evidence whatsoever for the intermediacy of radical anionic species.

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Section: Discussionsupporting

confidence: 90%

Electrochemical Oxidation ofσ-Complex-Type Intermediates in Aromatic Nucleophilic Substitutions

et al. 2001

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“…A pK a value of about 30-35 was estimated for these compounds (for diphenylmethane a pK a of 33.5 has been given [14] ), which should allow for a deprotonation with alcoholates. A pK a value of about 30-35 was estimated for these compounds (for diphenylmethane a pK a of 33.5 has been given [14] ), which should allow for a deprotonation with alcoholates.…”

Section: Resultsmentioning

confidence: 99%

Synthesis ofcis‐ andtrans‐Configured Octahydroperylenes

2017

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Lewis acid catalysed dimerization of 5‐methoxy‐1,2,3,4‐tetrahydronaphthalen‐1‐ol yields 4,10‐dimethoxy‐1,2,3,6b,7,8,9,12b‐octahydroperylene, in which the hydrogen atoms at the 6b‐ and 12b‐positions are trans‐arranged. This isomer is less stable than the corresponding cis isomer. Conversion of the trans‐configured meso compound into the racemic cis isomer is possible by heating with a radical initiator to give an anthracene derivative, which is then reduced under Birch conditions. The energetic course of these reactions was investigated with DFT calculations.

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“…This hypothesis is, of course, not new, an excellent case for electron donation into the sulfonyl group having been made some time ago by Bordwell et al (21). Such electron delocalization would be expected to be important in stabilizing the ground state (as shown) and also in inhibiting the development of a partial negative charge on the dicoordinated oxygen atom in the transition state.…”

Section: Prediction Of the Rates Ofreaction Of [O]mentioning

confidence: 84%

Betylates. 2. The formation and high reactivity of alkyl [0]betylates

King¹,

Lee²

1981

Can. J. Chem.

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. Can. J. Chem. 59,362 (1981). Unhindered primary alkyl N,N-dimethylsulfamates (1) react with methyl fluorosulfate to give the corresponding alkyl fluorosulfates (3) and the betaine, M~,&so,-(4), evidently by way of the intermediate alkyl [Olbetylate fluorosulfate (2); with certain other alkyl esters (1) products of substitution, elimination, and rearrangement are formed. The reaction not only provides a potentially useful route to simple alkyl fluorosulfates, but serves to demonstrate the powerful nucleofugality of the [Olbetylate group. To obtain a method for predicting the reactivity of [Olbetylates, we have compared substituent parameters with rate constants in four series of nucleophilic displacements involving esters of the general structure ROS02Z; correlation (of log k) with o* is mediocre but a new parameter, o : , with a "15% resonance" contribution as defined by Swain and Lupton, gives good to excellent agreement in the four reaction series. Evidence is presented for formation of the 7-norbornyl cation via the [Olbetylate from 7-norbornyl N,N-dimethylsulfamate and methyl fluorosulfate. Comparison with what is known of the reactivities of 7-norbornyl p-toluenesulfonate and trifluoromethanesulfonate esters serves to confirm that [0] betylates are among the most nucleofugal functions of which a derivative has been fully characterized.JAMES FREDERICK KING et TERESA MEE-LING LEE. Can. J. Chem. 59,362 (1981). Introduction more reactive than even the "super sulfonates". In the accompanying paper (1) we have reported Accordingly when we had determined that an aryl that phenyl N,N-dimethylsulfamate reacts with [Olbet~late could be prepared from an aryl N,Nmethyl fluorosulfate to yield the first example of an dimethylsulfamate, we quickly turned our attention isolable "[Qlbetylate" (i.e. trialkylammoniosul-to the corres~onding reaction of alkyl N,Nfate) ester.2 dimethylsulfamates. This paper describes our study of this reaction and our observation of the

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Acidities of carbon acids. VII. Conjugation and strain in some cyclopropyl anions

Cited by 88 publications

References 3 publications

Electrochemical Oxidation ofσ-Complex-Type Intermediates in Aromatic Nucleophilic Substitutions

Electrochemical Oxidation ofσ-Complex-Type Intermediates in Aromatic Nucleophilic Substitutions

Synthesis ofcis‐ andtrans‐Configured Octahydroperylenes

Betylates. 2. The formation and high reactivity of alkyl [0]betylates

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