53102-81-1Relevant articles and documents
Water-stable helical structure of tertiary amides of bicyclic β-amino acid bearing 7-azabicyclo[2.2.1]heptane. Full control of amide cis-trans equilibrium by bridgehead substitution
Hosoya, Masahiro,Otani, Yuko,Kawahata, Masatoshi,Yamaguchi, Kentaro,Ohwada, Tomohiko
scheme or table, p. 14780 - 14789 (2010/12/19)
Helical structures of oligomers of non-natural β-amino acids are significantly stabilized by intramolecular hydrogen bonding between main-chain amide moieties in many cases, but the structures are generally susceptible to the environment; that is, helices may unfold in protic solvents such as water. For the generation of non-hydrogen-bonded ordered structures of amides (tertiary amides in most cases), control of cis-trans isomerization is crucial, even though there is only a small sterical difference with respect to cis and trans orientations. We have established methods for synthesis of conformationally constrained β-proline mimics, that is, bridgehead-substituted 7-azabicyclo[2.2.1]heptane-2-endo-carboxylic acids. Our crystallographic, 1D- and 2D-NMR, and CD spectroscopic studies in solution revealed that a bridgehead methoxymethyl substituent completely biased the cis-trans equilibrium to the cis-amide structure along the main chain, and helical structures based on the cis-amide linkage were generated independently of the number of residues, from the minimalist dimer through the tetramer, hexamer, and up to the octamer, and irrespective of the solvent (e.g., water, alcohol, halogenated solvents, and cyclohexane). Generality of the control of the amide equilibrium by bridgehead substitution was also examined.
Scope of the directed dihydroxylation: Application to cyclic homoallylic alcohols and trihaloacetamides
Donohoe, Timothy J.,Mitchell, Lee,Waring, Michael J.,Helliwell, Madeleine,Bell, Andrew,Newcombe, Nicholas J.
, p. 2173 - 2186 (2007/10/03)
The synthesis and directed dihydroxylation of a range of cyclic alkenes was investigated. Both homoallylic alcohols and homoallylic trihaloacetamides were found to be efficient directing groups, giving rise to good to excellent levels of remote asymmetric induction with OsO4-TMEDA. Interestingly, in all cases examined, trifluoroacetamides were found to be superior to trichloroacetamides as directing groups and an argument is presented which rationalises this observation.
Solvolytic Rearrangements of Azabicyclic Compounds. Part 1. Identification of Products
Bastable, John W.,Cooper, Anthony J.,Dunkin, Ian R.,Hobson, John D.,Riddell, William D.
, p. 1339 - 1345 (2007/10/02)
The products of solvolysis of 2β-hylogeno-derivatives of 7-methyl-7-azabicycloheptane, 8-methyl-8-azabicyclooctane, 9-methyl-9-azabicyclo-- and --nonane, and 7-methyl-7-azabicyclooctane, have been isolated and characteri
