By nitrogen nucleophile

Formal replacement of one of the bulky halogens in polyhalogenofluoro-ethanes by nitrogen nucleophiles occurs through the intermediate formation of fluorinated olefins [91, 92] (see equation 47) (equation 79). 

The replacement of reactive aromatic fluonne by nitrogen nucleophiles is a well-known process for the preparation of aromatic amines The aromatic fluonne IS activated by the presence of electron-withdrawing substituents on the aromatic ring, especially in ortho and para positions [57 38, 39] (equations 25-27)... 

The regioselective ring-opening of vinyloxiranes by nitrogen nucleophiles offers an attractive route to vie-amino alcohols, compounds of much recent interest. As with oxygen nucleophiles, the stereochemistry of the reaction can be controlled by choice of reaction conditions aminolysis of 25, for example, affords anti-amino alcohol 26 in excellent yield and diastereoselectivity (Scheme 9.21) [48, 96, 97], and... 

The advantage of the nitro group as radical precursor is best seen in the context of intramolecular nucleophilic trapping of alkene radical cations by nitrogen nucleophiles, when no cyclization was observed prior to treatment... 

Tetraethylammonium iodide, 46 Triphenylphosphine-Diethyl azodi-carboxylate-Lithium halides, 332 of alcohols by nitrogen nucleophiles Dichlorotris(triphenylphosphine)-ruthenium(II), 107 Diethoxytriphenylphosphorane, 109 Diphosphorus tetraiodide, 127 Triphenylphosphine-Diethyl azodicar-boxylate, 332... 

Ring Opening by Nitrogen Nucleophiles P-Amino Amides and P-Amino... 

Ring Opening by Nitrogen Nucleophiles fl-Amino Amides and fi-Amino Acid-Derived Peptides... 

An Sn2 reaction with anchimeric assistance (via formation of a bicyclic aziridinium ion intermediate) has been proposed for the nucleophilic substitution of trans-2-substituted 3-piperidinol mesylates by nitrogen nucleophiles with retention of trans... 

In the penem series, 2-(heteroatom-substituted)-methyl derivatives have been similarly prepared via the 2-(hydro-xymethyl) key intermediate 71. Some examples of this C-2 functionalization are illustrated in Scheme 39 <1990H(30)799, 1995JME4244>. The reactions involved are O-acylation 72, O-arylation 73 by Mitsunobu coupling, and substitution by nitrogen nucleophiles 74 after OH activation by mesylation. 

It is well known that nucleophiles such as ammonia and amines are able to open pyran-2-one rings. The resultant ring-opened products are often able to recyclize under acidic conditions to yield pyridone and benzene derivatives. This section is mainly concerned with ring-transformation reactions induced by nitrogen nucleophiles not previously discussed <1984CHEC>, as well as some novel chemistry involving nitrogen nucleophiles. 

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