Which of the leaving groups attached to the "R" has a higher nucleophilicity: "R-OH"_2^+, "R-OEt", "R-Br" ?

1 Answer
Jan 6, 2015

EtO⁻ has the highest nucleophilicity.

The leaving groups are H₂O, EtO⁻, and Br⁻.

The best nucleophiles have a negative charge, so that rules out H₂O as a candidate.

Br⁻ is the conjugate base of the strong acid, HBr. So Br⁻ is a weak base and a poor nucleophile.

EtO⁻ is the conjugate base of the weak acid EtOH. So EtO⁻ is a strong base and the best nucleophile of the three.