Reduction nucleophilic addition reactions

The synthetic potential of the obtained phosphonates has been demonstrated in electron-deficient iminophosphonates by their easy functionalisation to afford various acyclic and heterocyclic derivatives with an aminophosphonic fragment by the use of reductive nucleophilic addition reactions, direct aminoallg lation of electron-rich heterocycles, cyclocondensations, and dipolar cycloaddition reactions. In the subsubsection devoted to reactions of phosphonates, ketophosphonates, vinylphosphonates, alkinylphosphonates, vinyl- and vinylidenebisphos-phonates were widely used as organophosphorus reagents. 

Reductive amination takes place by the pathway shown in Figure 24.4. An imine intermediate is first formed by a nucleophilic addition reaction (Section 19.8), and the C=N bond of the imine is then reduced. 

The carbonyl group of aldehydes and ketones may be reduced to an alcohol group by a nucleophilic addition reaction that appears to involve hydride as the nucleophile. The reduction of the carbonyl group may be interpreted as nucleophilic attack of hydride onto the carbonyl carbon, followed by abstraction of a proton from solvent, usually water. 

Also other reaction types have been dealt with in CHEC(1984) and CHEC-II(19%) like reduction to alcohols (e.g., sodium borohydride), Wolff Kishner reduction, nucleophilic addition via reaction with Grignard reagents or organo-lithium compounds, and formation of imine type functional groups (e.g., hydrazones). New examples are the reaction of... 

Indole, l-methyl-2-sulfonamido-tautomerism, 4, 200 Indole, l-methyl-3-sulfonamido-tautomerism, 4, 200 Indole, (methylthio)-synthesis, 4, 368 Indole, 3-(methylthio)-synthesis, 4, 338, 368 Indole, l-methyl-3-vinyl-oxidation, 4, 280 Indole, nitro-rearrangement, 4, 297 Indole, 3-nitro-nitration, 4, 211, 213 reduction, 4, 362 synthesis, 4, 210, 363 Indole, 5-nitro-synthesis, 4, 211, 363 Indole, nitroso-rearrangement, 4, 297 Indole, 1-nitroso-reduction, 4, 362 Indole, 3-nitroso-reduction, 4, 362 Indole, nitrovinyl-cycloaddition reactions, 4, 284 Indole, 3-(2-nitrovinyl)-nucleophilic addition reactions, 4, 281 Indole, perhydro-structure, 4, 196 Indole, 2-phenyl-metabolism, 1, 228 3-substituted ipso substitution, 4, 212 synthesis, 4, 126 Indole, 3-phenyl-... 

The high 77-deficiency at C-7 is also apparent from the nucleophilic addition reaction with sodium borohydride selective formation of the 6,7-dihydro derivative (566) results with this reagent. The reaction may also proceed further by reductive loss of the 7-substitutent (76CPB235). In the pyrazine analogue (567) both LAH and sodium borohydride treatment lead to saturation of the pyrazine ring (78JOC341). 

Just as addition of a Grignard reagent to an aldehyde or ketone yields an alcohol, so does addition of hydride ion, H (Section 17.4). Although the details of carbonyl-group reductions arc complex, LiAll-14 and N aBH4 act as if they were donors of hydride ion in a nucleophilic addition reaction (Figure 19.7).. Addition of water or aqueous acid after the hydride addition step protonates the tetrahedral alkoxide intermediate and gives the alcohol product. 

Nucleophilic addition reactions of aldehydes and ketones (a) Addition of hydride reduction (Section 19.8)... 

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