Application of Oxidative Ring Opening/Ring Closing by Reductive Amination Protocol for the Stereocontrolled Synthesis of Functionalized Azaheterocycles

The current Account gives an insight into the synthesis of some N-heterocyclic β-amino acid derivatives and various functionalized saturated azaheterocycles accessed from substituted cycloalkenes via ring C=C bond oxidative cleavage followed by ring closing across double reductive amination. The ring-cleavage protocol has been accomplished according to two common approaches: a) Os-catalyzed dihydroxylation/NaIO4 vicinal diol oxidation and b) ozonolysis. A comparative study on these methodologies has been investigated. Due to the everincreasing relevance of organofluorine chemistry in drug research as well as of the high biological potential of β-amino acid derivatives several illustrative examples to the access of various fluorine-containing piperidine or azepane β-amino acid derivatives are also presented in the current Account. 1 Introduction 2 Olefin-Bond Transformation by Oxidative Ring Cleavage 3 Synthesis of Saturated Azaheterocycles via Oxidative Ring-Opening/Ring-Closing Double Reductive Amination 3.1 Importance of Fluorine-Containing Azaheterocycles in Pharmaceutical Research 3.2 Synthesis of Azaheterocyclic Amino Acid Derivatives with a Piperidine or Azepane Framework through Oxidative Ring Opening/Reductive Amination 3.2.1 Synthesis of Piperidine β-Amino Esters 3.2.2 Synthesis of Azepane β-Amino Esters 3.2.3 Synthesis of Fluorine-Containing Piperidine γ-Amino Esters 3.3 Synthesis of Tetrahydroisoquinoline Derivatives through Oxidative Ring Opening/Reductive Amination Protocol 3.4 Synthesis of Functionalized Benzazepines through Reductive Amination 3.4.1 Synthesis of Benzo[c]azepines 3.4.2 Synthesis of Benzo[d]azepines 3.5 Synthesis of Various N-Heterocycles via Ozonolysis/Reductive Amination 3.5.1 Synthesis of Compounds with an Azepane Ring 3.5.2 Synthesis of Piperidine β-Amino Acids and Piperidine-Fused β-Lactams 3.5.3 Synthesis of γ-Lactams with a Piperidine Ring 3.5.4 Synthesis of other N-Heterocycles 4 Summary and Outlook 5 List of Abbreviations