Synthesis of Enniatin-like Cyclic Depsipeptidesvia ‘Direct Amide Cyclization’
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چکیده
منابع مشابه
Transformation of 5-Hydroxy- to (5-Chloropentanoyl)amino Derivatives under ‘Direct Amide Cyclization’ Conditions
The application of the ‘direct amide cyclization’ conditions to the linear delta-hydroxy diamide 11 is described (Scheme 3). Instead of the cyclization to the expected nine-membered cyclodepsipeptide, only the chloro acid 12 was obtained. Its formation could be explained by consecutive formation of the 1,3-oxazol-5(4H)-one 16 and the six-membered imino lactone 17 as intermediates (Scheme 4). Th...
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Cyclization vs. cyclization/dimerization in o-amidostilbene radical cation cascade reactions: the amide question.
The n-butyramido, isobutyramido, benzamido, and furancarboxamido functions profoundly modulate the electronics of the stilbene olefinic and NH groups and the corresponding radical cations in ways that influence the efficiency of the cyclization due presumably to conformational and stereoelectronic factors. For example, isobutyramido- stilbene undergoes FeCl(3) promoted cyclization to produce on...
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A simple and mild process was developed for the highly stereoselective synthesis of halogenated bicyclic [4.3.0] and [3.3.0] γ-lactams, possessing four stereocenters, from easily available cyclic 2-enynamides. The reaction required only an inexpensive iron(II) halide under dry air and was tolerant of aryl, heteroaryl, and alkyl groups at the alkyne terminus.
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ژورنال
عنوان ژورنال: Helvetica Chimica Acta
سال: 2006
ISSN: 0018-019X,1522-2675
DOI: 10.1002/hlca.200690069