Publication

Switching on and off metalation sites in triarylphosphines by manipulating substrate coordination

Manfred Schlosser
1998
Journal Articles

Abstract

The inductive electron-withdrawing effect of the pos. charged P atom in triarylphosphine-BH3 adducts is largely compensated by the steric congestion caused in its vicinity. Therefore, Ph3P.BH3 reacts only sluggishly even with superbasic reagents, and products derived from ortho-metalated intermediates by their trapping with electrophiles are formed only in poor yield. However, the BH3 adducts of 3-MeOC6H4PPh2 and 3-FC6H4PPh2 are readily deprotonated at the hetero-adjacent para position and converted into final products in high yields. The P-remote regioselectivity of these phosphine-BH3 zwitterions is complementary to that previously obsd. with the corresponding phosphine oxides. [on SciFinder (R)]

Official source

https://infoscience.epfl.ch/entities/publication/fd5474e8-ef03-4c22-99a7-1069702c2adf

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Manfred Schlosser
1998
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/fd5474e8-ef03-4c22-99a7-1069702c2adf

About this result

Related concepts (18)

Organoboron chemistry

Organoboron chemistry or organoborane chemistry is the chemistry of organoboron compounds or organoboranes, which are chemical compounds of boron and carbon that are organic derivatives of borane (BH3), for example trialkyl boranes. . Organoboron compounds are important reagents in organic chemistry enabling many chemical transformations, the most important ones being hydroboration and carboboration. Reactions of organoborates and boranes involve the transfer of a nucleophilic group attached to boron to an electrophilic center either inter- or intramolecularly.

Inductive effect

In chemistry, the inductive effect in a molecule is a local change in the electron density due to electron-withdrawing or electron-donating groups elsewhere in the molecule, resulting in a permanent dipole in a bond. It is present in a σ (sigma) bond, unlike the electromeric effect which is present in a π (pi) bond. The halogen atoms in an alkyl halide are electron withdrawing while the alkyl groups have electron donating tendencies.

Mesomeric effect

In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound. It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. This change in electron arrangement results in the formation of resonance structures that hybridize into the molecule's true structure. The pi electrons then move away from or toward a particular substituent group.