1,3-Asymmetric Induction via 1,5-Hydrogen Atom Translocation Reactions. Highly Enantioselective Synthesis of β-Substituted β-Amino Acids

Total Synthesis of (±)-Goniomitine via Radical Translocation

The aspidosperma alkaloid goniomitine was synthesized in six steps from 2-ethyl-δ-valerolactam. The convergent strategy features an Ullman coupling to assemble the required carbon atoms. A complexity-generating radical translocation reaction was used to build the indole architecture.

Synthesis of 2-Substituted-5-halo-2,3-dihydro-4(H)-pyrimidin-4-ones and Their Derivatization Utilizing the Sonogashira Coupling Reaction in the Enantioselective Synthesis of α-Substituted β-Amino Acids

A convenient, one-pot procedure for the synthesis of 1-benzoyl-2(S)-substituted-5-iodo-2,3-dihydro-4(H)-pyrimidin-4-ones by tandem decarboxylation/beta-iodination of the corresponding 6-carboxy-perhydropyrimidin-4-ones was developed. In addition, several 1-benzoyl-2(S)-substituted-5-bromo-2,3-dihydro-4(H)-pyrimidin-4-ones were readily prepared by bromination of 1-benzoyl-2(S)-substituted-2,3-dihydro-4(H)-pyrimidin-4-ones. Subsequently, Sonogashira coupling of the halogenated heterocyclic enones with various terminal alkynes produced 1-benzoyl-2(S)-isopropyl-5-alkynyl-2,3-dihydro-4(H)-pyrimidin-4-ones in good yields. Hydrogenation of the unsaturated C-C moieties in the Sonogashira products followed by acid hydrolysis afforded highly enantioenriched alpha-substituted beta-amino acids.

A general route to protected quaternary α-amino acids from β-amino alcohols via a stereocontrolled radical approach

A radical-based approach facilitates the highly stereocontrolled functionalisation of beta-amino alcohols, opening up a new, generally applicable methodology for the preparation of quaternary alpha-amino acids.