and alkyl groups seem to be þI in some cases and I in others48 (see also p. 391). Similarly, it is clear that the field-effect order of alkyl groups attached to unsaturated systems is tertiary >secondary >primary > CH3, but this order is not always maintained when the groups are attached to saturated systems. Deuterium is electrondonating with respect to hydrogen.49 Other things being equal, atoms with sp bonding generally have a greater electron-withdrawing power than those with sp2 bonding, which in turn have more electron-withdrawing power than those with sp3 bonding.50 This accounts for the fact that aryl, vinylic, and alkynyl groups are I. Field effects always decrease with increasing distance, and in most cases (except when a very powerful þI orI group is involved), cause very little difference in a bond four bonds away or more. There is evidence that field effects can be affected by the solvent.51 For discussions of field effects on acid and base strength and on reactivity, see Chapters 8 and 9, respectively.
and alkyl groups seem to be þI in some cases and I in others48 (see also p. 391). Similarly, it is clear that the field-effect order of alkyl groups attached to unsaturated systems is tertiary >secondary >primary > CH3, but this order is not always maintained when the groups are attached to saturated systems. Deuterium is electrondonating with respect to hydrogen.49 Other things being equal, atoms with sp bonding generally have a greater electron-withdrawing power than those with sp2 bonding, which in turn have more electron-withdrawing power than those with sp3 bonding.50 This accounts for the fact that aryl, vinylic, and alkynyl groups are I. Field effects always decrease with increasing distance, and in most cases (except when a very powerful þI orI group is involved), cause very little difference in a bond four bonds away or more. There is evidence that field effects can be affected by the solvent.51 For discussions of field effects on acid and base strength and on reactivity, see Chapters 8 and 9, respectively.
การแปล กรุณารอสักครู่..
and alkyl groups seem to be þI in some cases and I in others48 (see also p. 391). Similarly, it is clear that the field-effect order of alkyl groups attached to unsaturated systems is tertiary >secondary >primary > CH3, but this order is not always maintained when the groups are attached to saturated systems. Deuterium is electrondonating with respect to hydrogen.49 Other things being equal, atoms with sp bonding generally have a greater electron-withdrawing power than those with sp2 bonding, which in turn have more electron-withdrawing power than those with sp3 bonding.50 This accounts for the fact that aryl, vinylic, and alkynyl groups are I. Field effects always decrease with increasing distance, and in most cases (except when a very powerful þI orI group is involved), cause very little difference in a bond four bonds away or more. There is evidence that field effects can be affected by the solvent.51 For discussions of field effects on acid and base strength and on reactivity, see Chapters 8 and 9, respectively.
การแปล กรุณารอสักครู่..