The first examples of highly enantioselective [2,3]-sigmatropic rearrangements of acyclic allylic ammonium ylids are reported. Thus, a range of N-{2'-[(N'-allyl-N',N'-dialkyl)ammonium]}acetyl camphor sultams undergo rearrangement at 0 degrees C in DME solution with high diastereofacial control (up to 99:1 dr) to give allylglycines in generally high yield. The power of the method has been demonstrated in a rapid and efficient synthesis of (R)-allyl glycine.

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The factors affecting the copper-catalyzed rearrangement of ammonium ylids derived from tetrahydropyridines and diazoesters have been examined,and the first examples of high-yielding metal-catalyzed [2,3]-sigmatropic rearrangements of a wide range of such ylids are reported. The nature of the alpha-substituent in the diazo component of the reaction has a dramatic effect upon the yields of the reaction, with electron-withdrawing substituents enhancing the yield of the reaction. [reaction: see text]

The first examples of sigmatropic rearrangements of ene-endo-spirocyclic, tetrahydropyridine-derived ammonium ylids are reported. Thus, spiro[6.7]-ylids rearrange primarily by a [2,3]-pathway, whereas the analogous [6.6]-ylids rearrange by [1,2]- and [2,3]-mechanisms in roughly equal proportions. This method serves as a rapid entry to the core of a range of alkaloids bearing a pyrrolo[1,2-a]azepine or octahydroindolizidine nucleus.

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The title reaction proceeds via the reaction of diazo esters with N-methyltetrahydropyridines. A range of diazo and amine components has been used to generate a collection of structurally diverse, densely functionalized pyrrolidines in good yields. The nature of the α-substituent in the diazo component has a dramatic effect upon the yields of the reaction: electron-withdrawing substituents enhance the yield. -(ROBERTS, E.; SANCON, J. P.; SWEENEY*, J. B.; WORKMAN, J. A.; Org. Lett. 5 (2003) 25, 4775-4777; Dep. Chem., Univ. Reading, Whiteknights, Reading, Berkshire RG6 6AD, UK; Eng.) -Steudel 16-119

Aminocarboxylic acids (hydrazinocarboxylic acids) and esters P 0270Asymmetric [2,3]-Rearrangement of Glycine-Derived Allyl Ammonium Ylids. -N-Allylic glycine salts bearing a camphorsultam auxiliary undergo [2,3] rearrangement to give allylglycine derivatives with excellent enantiocontrol. Substrates bearing the (2R)-configured auxiliary afford predominantly (2'S)-configured products, while the use of the (2S)-auxiliary gives (2'R)-products. Allyl migration is favored over benzyl migration. For ammonium salts (IX) high diastereoselectivities are observed for the corresponding products. Ammonium salt (XII) having the chiral auxiliary attached to the allyl substituent rather than the glycine moiety also undergoes the rearrangement to give β-ethenyl aspartate derivative (XIII) as major stereoisomer. The route to allylglycine (V) via product (IIb) represents a new and efficient method for this compound. -(WORKMAN, J. A.; GARRIDO, N. P.; SANCON, J.; ROBERTS, E.; WESSEL, H. P.; SWEENEY*, J. B.; J.

Ring closure reactions O 0130 A Practical Route to Pyrazines and Quinoxalines, and an Unusual Synthesis of Benzimidazoles. -A flexible approach to benzimidazoles, quinoxalines and pyrazines, cf. compounds (VI), (VIII), (IX) and (XI) uses masked keto-aldehydes, e.g. (IV), which are prepared by using xanthate transfer technology. -(MOUGIN, C.; SANCON, J.; ZARD*, S. Z.; Heterocycles 74 (2007) 1, 211-218; Dep. Chem., DCMR, Ec. Polytech., F-91128 Palaiseau, Fr.; Eng.) -K. Schneider 25-032