Control of the ambident reactivity of the nitrite ion

TY - JOUR

T1 - Control of the ambident reactivity of the nitrite ion

AU - Dong, Hai

AU - Rahm, Martin

AU - Thota, Niranjan

AU - Deng, Lingquan

AU - Brinck, Tore

AU - Ramström, Olof

PY - 2013/1/28

Y1 - 2013/1/28

N2 - In previous studies, it was reported that a neighbouring equatorial ester group is essential for a good yield of nitrite-mediated triflate inversion, whereas with neighbouring benzyl ether groups or axial ester groups, mixtures are generally produced. In the present study, the origin of this difference was addressed. The ambident reactivity of the nitrite ion has been found to be the cause of the complex product formation observed, which can be controlled by a neighbouring equatorial ester group. Both N-attack and O-attack occur in the absence of the ester group, whereas O-attack is favoured in its presence. A neighbouring group assistance mechanism is proposed, in addition to steric effects, based on secondary interactions between the neighbouring ester group and the incoming nucleophile. High-level quantum mechanical calculations were carried out in order to delineate this effect. The theoretical results are in excellent agreement with experiments, and suggest a catalytic role for the neighbouring equatorial ester group.

AB - In previous studies, it was reported that a neighbouring equatorial ester group is essential for a good yield of nitrite-mediated triflate inversion, whereas with neighbouring benzyl ether groups or axial ester groups, mixtures are generally produced. In the present study, the origin of this difference was addressed. The ambident reactivity of the nitrite ion has been found to be the cause of the complex product formation observed, which can be controlled by a neighbouring equatorial ester group. Both N-attack and O-attack occur in the absence of the ester group, whereas O-attack is favoured in its presence. A neighbouring group assistance mechanism is proposed, in addition to steric effects, based on secondary interactions between the neighbouring ester group and the incoming nucleophile. High-level quantum mechanical calculations were carried out in order to delineate this effect. The theoretical results are in excellent agreement with experiments, and suggest a catalytic role for the neighbouring equatorial ester group.

KW - Journal Article

U2 - 10.1039/c2ob26980e

DO - 10.1039/c2ob26980e

M3 - Journal article

C2 - 23223642

SN - 1477-0520

VL - 11

SP - 648

EP - 653

JO - Organic & Biomolecular Chemistry

JF - Organic & Biomolecular Chemistry

IS - 4

ER -