Lander rearrangement

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The Lander rearrangement is a name reaction in organic chemistry . It is the thermal conversion of an alkyl imidate into an N -alkylamide in the presence of an alkylating substance.

The reaction was first reported by Henry L. Wheeler, Treat B. Johnson, and David F. McFarland in 1899. George Druce Lander researched this more intensively from 1900 and thus gave the reaction its name.

Overview reaction

During the reaction, the alkylating substance - z. B. Iodomethane - to rearrangements. An N -dialkylamide is obtained as the product .

Overview reaction of the Lander rearrangement

Reaction mechanism

Different mechanisms have been proposed and experimentally investigated for the Lander rearrangement. The following mechanisms are described in the literature and represent an illustration of what such a reaction mechanism might look like.

two possible mechanisms of Lander rearrangement

Path A : In this mechanism, an electron pair of the N – C double bond of the alkyl imidate 1 attaches to the methyl group of the iodomethane, which leads to further electron rearrangements. With elimination of an iodoethyl, the N -dialkylamide 2 is formed .

Path B : Compared to mechanism A , a lone pair of electrons from the nitrogen of the alkyl imidate 1 is attached to the methyl group of the iodomethane. This creates the intermediate cation 3 . The attack of the anion leads to further electron rearrangement in the molecule and with elimination of iodoethyl, the N -dialkylamide 2 is obtained as the product .

Individual evidence

  1. ^ A b Zerong Wang: Comprehensive Organic Name Reactions and Reagents , Wiley, 2010, ISBN 9780470638859 , pp. 1713-1716, doi: 10.1002 / 9780470638859 .
  2. ^ Henry L. Wheeler, Treat B. Johnson, David F. McFarland: ON THE MOLECULAR REARRANGEMENT OF UNSYMMETRICAL ACYLAMIDINES INTO ISOMERIC SYMMETRICAL DERIVATIVES. In: Journal of the American Chemical Society . tape 25 , no. 8 , August 1903, p. 787-798 , doi : 10.1021 / ja02010a001 .
  3. ↑ GD Lander: Alkylation by Means of dry silver oxide and alkyl Halides In: Journal of the Chemical Society, Transactions 77, 1900, p 729, doi: 10.1039 / CT9007700729 .