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Methyl Substitution Destabilizes Alkyl Radicals.

ABSTRACT: We have quantum chemically investigated how methyl substituents affect the stability of alkyl radicals Me_m H_3-m C⋅ and the corresponding Me_m H_3-m C-X bonds (X = H, CH₃ , OH; m = 0 - 3) using density functional theory at M06-2X/TZ2P. The state-of-the-art in physical organic chemistry is that alkyl radicals are stabilized upon an increase in their degree of substitution from methylm H_3-m C⋅ radical is destabilized with increasing substitution. The reason that the corresponding C-H bond nevertheless becomes weaker is that substitution destabilizes the sterically more congested Me_m H_3-m C-H molecule even more.

SUBMITTER: Blokker E

PROVIDER: S-EPMC9545886 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature

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Methyl Substitution Destabilizes Alkyl Radicals.

Blokker Eva E van Zeist Willem-Jan WJ Sun Xiaobo X Poater Jordi J van der Schuur J Martijn JM Hamlin Trevor A TA Bickelhaupt F Matthias FM

Angewandte Chemie (International ed. in English) 20220801 36

We have quantum chemically investigated how methyl substituents affect the stability of alkyl radicals Mem H3-m C⋅ and the corresponding Mem H3-m C-X bonds (X = H, CH3 , OH; m = 0 - 3) using density functional theory at M06-2X/TZ2P. The state-of-the-art in physical organic chemistry is that alkyl radicals are stabilized upon an increase in their degree of substitution from methyl<primary<secondary<tertiary, and that this is the underlying ca ...[more]

PMID: 35819818

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