1,2-carbon-to-nitrogen migration

Migration from nitrogen to carbon is observed also in aza-Cope rearrangement [76] Ring expansion occurs in thermal rearrangement of azindine denvauves [77] (equation 17)... 

E. Nitrogen-to-Carbon, Oxygen-to Carbon, and SulfuMo-Carbon Migration... 

The formation of tluorinated Q -hydroxy-jS-imino esters (180) by treatment of fluorinated imino ethers (179) with lithium 2,2,6,6-tetramethylpiperidide has been reported. A possible explanation for this interesting intramolecular rearrangement is proposed in Scheme 64. Acyclic imides derived from primary benzylic amines and amino acid esters have been found to undergo a novel nitrogen to carbon acyl migration via a base-generated carbanion to yield the corresponding a-amino... 

Examples exist of rearrangements in which a halogen atom migrates from annular nitrogen to carbon, or from one ring carbon to another ( halogen-dance or transmetalation). Such processes occasionally have preparative importance, and they will be covered in the appropriate sections. 

McComsey, D. F., Maryanoff, B. E. 3-Aza-Cope Rearrangement of Quaternary N-Aiiyi Enammonium Saits. Stereospecific 1,3 Aiiyi Migration from Nitrogen to Carbon on a Tricyciic Tempiate. J. Org. Chem. 2000, 65,4938-4943. 

An unusual migration of a trimethylsilyl group from nitrogen to carbon occurs in the reaction of the salt (155) with n-butyl-lithium. ... 

Other Methods.—No new phosph(m)azenes have been reported, but several unusual routes to phosph(v)azenes have appeared. In one case, migration of the silyl group from nitrogen to carbon in a Wittig reagent results in the formation of the phosph-azene (28). Descriptions of further conventional examples of deprotonation of... 

Gandhi et al. report that the irradiation of the lactams (208) brings about a 1,3-migration of benzyl or allyl groups from nitrogen to carbon to afford the derivatives (209). Irradiation of the )7-methyl derivative follows a different path and yields the aziridine derivative (210). The formation of this compound could be considered to arise by an oxa-di-m-methana process or... 

According to Wittig,97 the base (sodium alkoxide, phenyllithium, or sod-amide) removes a proton from the -carbon atom, yielding the unstable ylide in which the benzyl group then migrates from nitrogen to carbon. 

Summary Pure and mixed substituted indoyl-, pyrroyl-, and furanyl-silanes are formed in the reaction of heteroaromatic compounds with lithium alkyls and halosilanes (1-3). Chains of silyl-bridged molecules are available (7). The crystal structure of a lithium derivative (10) is presented and the 1,2-silyl group migration from nitrogen to carbon is proved. Formation of a 16-membered macrocycle (12) containing four indole molecules is described. 

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