2026-10-14T20:22:15Z
https://api.figshare.com/v2/oai
oai:figshare.com:article/33900376
2026-09-17T16:05:49Z
category_1
category_4
category_7
category_12
category_24
category_873
category_734
category_132
portal_63
item_type_3
month_year_09_2026
Selectivity
in Homolytic Substitution at a Tertiary
Phosphine Center: Mechanistic Insights into Dealkanation Reaction
Bethany
J. M. Lawson (25033375)
Chao Dun Tan (16622362)
Georg Hähner (1319703)
David B. Cordes (809266)
Michael Bühl (1317231)
Alister S. Goodfellow (23227226)
Petr Kilian (1317228)
Biophysics
Biochemistry
Medicine
Cell Biology
Evolutionary Biology
Chemical Sciences not elsewhere classified
Biological Sciences not elsewhere classified
Infectious Diseases
tertiary phosphine center
methane formation compete
intensity uv irradiation
including ambient daylight
different alkyl substituents
>- butane occurs
140 ° c
comprehensive mechanistic investigation
2 transition state
centered radical expelled
h </ sub
tert </
n </
mechanistic insights
2 step
weakly bound
thermal conditions
synthesized precursors
substrates bearing
room temperature
induced preorganization
homolytic substitution
group ability
forming process
computational results
competitive elimination
carrying radical
calculations indicate
Here, we present a comprehensive mechanistic investigation
of a
transformation that reverses the usual reactivity of an established
radical P–C bond-forming process. Peri-substituted compounds
bearing tertiary and secondary phosphine groups undergo dealkanation
to afford an alkane and a diphosphine. To examine the influence of
the chain-carrying radical, we synthesized precursors with different
alkyl substituents at the tertiary phosphine center and correlated
the rates and selectivities of their reactions with computational
results. The reactivity is governed by the leaving-group ability of
the carbon-centered radical expelled in the S<sub>H</sub>2 step, which
is rate-limiting in most cases. Competitive elimination of propane
and <i>n</i>-butane occurs when both pathways are accessible,
whereas only propane is eliminated when propane and methane formation
compete. Substrates bearing a <i>tert</i>-butyl group eliminate
isobutane even at low temperature. Low-intensity UV irradiation, including
ambient daylight, promotes the reaction at room temperature at rates
comparable to those observed under thermal conditions at 140 °C.
Calculations indicate a weakly bound, phosphoranyl-radical-like S<sub>H</sub>2 transition state and reveal that peri-induced preorganization
and altered bond strengths enable this unusual reactivity.
2026-09-17T00:00:00Z
Dataset
Dataset
10.1021/acs.inorgchem.6c03650.s001
https://figshare.com/articles/dataset/Selectivity_in_Homolytic_Substitution_at_a_Tertiary_Phosphine_Center_Mechanistic_Insights_into_Dealkanation_Reaction/33900376
CC BY-NC 4.0