ABSTRACT
A series of 6,6-dihalo-2-azabicyclo[3.1.0]hexane and 7,7-dihalo-2-azabicyclo[4.1.0]heptane compounds were prepared by the reaction of dihalocarbene species with N-Boc-2,3-dihydro-1H-pyrroles or -1,2,3,4-tetrahydropyridines. Monochloro substrates were synthesised as well, using a chlorine-to-lithium exchange reaction. The behaviour of several aldehydes and ketones under reductive amination conditions with deprotected halogenated secondary cyclopropylamines was investigated, showing that this transformation typically triggers cyclopropane ring cleavage to give access to interesting nitrogen-containing ring-expanded products.
ABSTRACT
In the past decade, the Overman rearrangement, an important C-N bond forming reaction, has been intensely used in the synthesis of natural products, synthetic intermediates, building blocks and valuable compounds. This review documents the reports on this rearrangement reaction since 2005. The reaction has been tactfully used to introduce amine functionality in the synthesis of natural products. It is a one-pot process using the intermediate imidate which upon rearrangement generates the amide that can be hydrolysed to the amine. The method has tremendous potential for rapid modification of various amino compounds and can be combined with other Claisen-rearrangements or other reactions for one-pot processes for further exploration.
Subject(s)
Amines/chemistry , Biological Products/chemical synthesis , Biological Products/chemistry , Hydrolysis , Molecular StructureABSTRACT
Ethyl succinic anhydride and its d5-labeled version have been synthesized and applied to quantitative analysis of peptides in combination with MALDI or ESI mass spectrometry. These modifiers react with amino groups in the N-termini and lysine side chains in proteins, and therefore the combination of these modifiers was shown to be a useful tool for quantification of peptides and hence for proteomics research.
Subject(s)
Mass Spectrometry/methods , Peptides/chemistry , Succinic Anhydrides/chemical synthesis , Proteomics , Succinic Anhydrides/chemistryABSTRACT
A practical protecting group free synthesis of Hagen's gland lactones 1 and 2 is accomplished in four steps and 25.6 and 37.4% overall yields, respectively. The strategy relies on a one-pot conversion of D-glucono-δ-lactone to ß-hydroxy-γ-vinyl-γ-lactone, cross-metathesis, and iodocyclization-deiodinization as key steps.
