1
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Abstract
The kinetics of the ring‐opening reactions of thiophenolates with geminal bis(acceptor)‐substituted cyclopropanes in DMSO at 20 °C was monitored by photometric methods. The determined second‐order rate constants of the SN2 reactions followed linear relationships with Mayr nucleophilicity parameters (N/sN) and Brønsted basicities (pKaH) of the thiophenolates as well as with Hammett substituent parameters (σ) for groups attached to the thiophenolates. Phenyl‐substituted cyclopropanes reacted by up to a factor of 15 faster than their unsubstituted analogues, in accord with the known activating effect of adjacent π‐systems in SN2 reactions. Variation of the electronic properties of substituents at the phenyl groups of the cyclopropanes gave rise to parabolic Hammett relationships. Thus, the inherent SN2 reactivity of electrophilic cyclopropanes is activated by electron‐rich π‐systems because of the more advanced C1−C2 bond polarization in the transition state. On the other hand, electron‐poor π‐systems also lower the energetic barriers for the attack of anionic nucleophiles owing to attractive electrostatic interactions.
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Affiliation(s)
- Patrick M Jüstel
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany
| | - Alexandra Stan
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany
| | - Cedric D Pignot
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany
| | - Armin R Ofial
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany
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2
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Jüstel PM, Stan A, Pignot CD, Ofial AR. Cover Feature: Inherent Reactivity of Spiro‐Activated Electrophilic Cyclopropanes (Chem. Eur. J. 64/2021). Chemistry 2021. [DOI: 10.1002/chem.202103870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Patrick M. Jüstel
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Germany
| | - Alexandra Stan
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Germany
| | - Cedric D. Pignot
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Germany
| | - Armin R. Ofial
- Department Chemie Ludwig-Maximilians-Universität München Butenandtstr. 5–13 81377 München Germany
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3
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Jüstel PM, Rovó P, Mayr H, Ofial AR. Dynamics of the dimethyl sulfide exchange of (1,3‐diphenylallyl)dimethylsulfonium ions. J PHYS ORG CHEM 2021. [DOI: 10.1002/poc.4270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Patrick M. Jüstel
- Department Chemie Ludwig‐Maximilians‐Universität München Munich Germany
| | - Petra Rovó
- Department Chemie Ludwig‐Maximilians‐Universität München Munich Germany
| | - Herbert Mayr
- Department Chemie Ludwig‐Maximilians‐Universität München Munich Germany
| | - Armin R. Ofial
- Department Chemie Ludwig‐Maximilians‐Universität München Munich Germany
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4
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Abstract
Rate constants for the reactions of dialkyl chalcogenides with laser flash photolytically generated benzhydrylium ions have been measured photometrically to integrate them into the comprehensive benzhydrylium‐based nucleophilicity scale. Combining these rate constants with the previously reported equilibrium constants for the same reactions provided the corresponding Marcus intrinsic barriers and made it possible to quantify the leaving group abilities (nucleofugalities) of dialkyl sulfides and dimethyl selenide. Due to the low intrinsic barriers, dialkyl chalcogenides are fairly strong nucleophiles (comparable to pyridine and N‐methylimidazole) as well as good nucleofuges; this makes them useful group‐transfer reagents.
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Affiliation(s)
- Biplab Maji
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany.,Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246, India
| | - Xin-Hua Duan
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany.,Department of Chemistry, School of Chemistry, Xi'an Key Laboratory of Sustainable Energy Material Chemistry, Xi'an Jiaotong University, No. 28, Xianning West Road, Xi'an, 710049, P. R. China
| | - Patrick M Jüstel
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany
| | - Peter A Byrne
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany.,School of Chemistry, University College Cork, College Road, Cork, Ireland
| | - Armin R Ofial
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany
| | - Herbert Mayr
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377, München, Germany
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5
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Abstract
The nucleophilic reactivities of substituted thiophenolates were determined by following the kinetics of their reactions with a series of quinone methides (reference electrophiles) in DMSO at 20 °C. The experimentally determined second-order rate constants were analyzed according to the Mayr-Patz equation log k = sN(N + E) to derive the nucleophile-specific reactivity parameters N and sN for ten thiophenolate ions.
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Affiliation(s)
- Patrick M Jüstel
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
| | - Cedric D Pignot
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
| | - Armin R Ofial
- Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstraße 5-13, 81377 München, Germany
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