title: Design, synthesis, and evaluation of a new generation of modular nucleophilic glycine equivalents for the efficient synthesis of sterically constrained alpha-amino acids.
abstract: A new generation of modular achiral glycine equivalents have been evaluated with respect to their synthetic utility for the production of tailor-made, sterically constrained alpha-amino acids, which proved to be the most efficient approach developed to date for the synthesis of symmetrical alpha,alpha-disubstituted-alpha-amino acids. Among the new series of achiral glycine equivalents, one was found to be a superior glycine derivative for the Michael additions with various (R)- or (S)-N-(E-enoyl)-4-phenyl-1,3-oxazolidin-2-ones representing a general and practical synthesis of sterically constrained beta-substituted pyroglutamic acids. In particular, the application of these complexes allowed for the preparation of several beta-substituted pyroglutamic acids which include electron-releasing and sterically demanding substituents in the structure thus increasing the synthetic efficiency and expanding the generality of these Michael addition reactions.
authors.affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019, USA.
authors.forename: Trevor K
authors.initials: TK
authors.lastname: Ellis
authors.forename: Hisanori
authors.initials: H
authors.lastname: Ueki
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamada
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Ohfune
authors.forename: Vadim A
authors.initials: VA
authors.lastname: Soloshonok
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry* / Q000191:economics; D005998:Glycine / Q000737:chemistry*; D015394:Molecular Structure; D012995:Solubility; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D005998:Glycine