Seven-membered rings
RIS ID
95355
Abstract
This chapter reviews the chemistry of seven-membered heterocycles published in 2009 and presents the research focussing on the construction and reactions of these heterocyclic systems. In recent years, there appears to have been a trend toward more complex molecules with more than one heteroatom. Palladium-catalyzed intramolecular oxidative allylic C-H amination favor the formation of azepines. Intramolecular hydroamination with a zirconium complex gives cyclic amines including azepine and benzazepine derivatives in good yields. The gold-catalyzed cycliszation at the C-2 of indole onto a tethered alkyne occurrs preferentially to give the 8-endo-dig product, except when bulky phosphine ligands are used. While benzodiazepines and benzothiazepines continue to be important heterocyclic motifs in the synthesis of biologically active molecules, there has been resurgence in the synthesis of azepines and their fused derivatives. Reviews published on seven-membered heterocycles during 2009 included a summary of the strategies toward the synthesis of the stemona alkaloids that contain a pyrroloazepine system and the synthesis of 3-methylbenzoxepines and 3-methyl-1-benzoxepines.
Publication Details
Smith, J. A., Molesworth, P. P., Hyland, C. J. T. & Ryan, J. H. (2011). Seven-membered rings. In G. Gribble & J. A. Joule (Eds.), Progress in Heterocyclic Chemistry (pp. 491-536). Netherlands: Elsevier BV.