ChemInform Abstract: MOEGLICHKEIT EINER KONKURRENZ DER MEERWEIN‐PONNDORF‐RK. UND DER RED. DURCH ORGANO‐MAGNESIUMVERBINDUNGEN

Investigation of the mechanism of decyanation of 2,2-diphenylpropionitrile induced by LiAlH4

“…We mentioned above the reductive decyanation of aaminonitriles with the hydride ion via an S N 1 polar pathway. 7,8 In the LiAlH 4 reduction of nitrile 4, an S N 2 process seems unlikely, however, since (1) the cyano group has a poor leaving ability and (2) the attacked sp 3 carbon would be sterically hindered both by the methyl and the two phenyl substituents.…”

“…Different mechanisms operate depending on the reducing agent used: electron transfer (alkali metals), 1 radical chain (Bu 3 SnH, SmI 2 ) 2,3 and a polar mechanism (RLi, RMgX). [4][5][6] For the reductive decyanation of a-aminonitriles with LiAlH 4 , 7,8 an S N 1 mechanism with assistance of the amino group and formation of an iminium ion intermediate was proposed. The decyanation is also observed under more drastic conditions with KOH, 9 NaOH 10 or NaNH 2 .…”

The reductive decyanation reaction: chemical methods and synthetic applications

“…57,[65][66][67][68][69][70][71][72] The mechanism is a S N 1 process with formation of an iminium ion followed by an addition of the hydride ion (Scheme 8). 73 Several facts support this mechanism.…”

“…So Lewis acids, such as AlCl 3 , are able to promote decyanation in unfavorable cases. 73 Moreover, the decyanation pathway is favored with disubstituted α-aminonitriles. …”

The Bruylants and related reactions

“…This reaction generally is encountered for -aminonitriles unsubstituted at the -carbon. [13][14][15][16][17][18] An example is provided in Scheme 2 on piperidine and pyrrolidine derivatives 1a-b. 19 The reaction leads to ketones 2a-b with small amounts of dimers 4a-b formed from deprotonation by the Grignard reagent followed by condensation on the cyano group.…”