The SRN1' reaction.

Nucleophilic Substitution Reactions by Electron Transfer

“…Substitution at the α-carbon of m -O 2 NC 6 H 4 CH 2 Cl by a t -Bu group shifts the mechanism from polar to S RN 1. Similar results were observed in the 2-halomethyl-5-nitrofuran family 49a and in the reaction of p -nitrophenylallyl chlorides with different carbanions 49b…”

“…However, 2-(bromomethyl)-5-nitrofuran was assumed to afford substitution with PhS - and p -ClC 6 H 4 S - ions by an S RN 1 reaction, without mechanistic evidences . This pathway prevails when the benzylic carbon is substituted by a tert -butyl group (Table ) 49a18 Photoinduced Reactions of Nitrofuran, Thiophene, Pyrrole, and Pyridine Alkyl Derivatives with Nucleophiles in DMSO a a X as leaving group.…”

“…In the reactions of p -nitrophenylallyl chlorides with different carbanions the mechanism involved depends on the alkyl substituent R . The Me derivative undergoes S N 2 or S N 2‘, the i -Pr mixed S RN 1/S N 2, and the t- Bu only the S RN 1 mechanism (Scheme ) 49b. The particular regiochemistry of this S RN 1 reaction can be attributed to the steric hindrance of the R substituent, which disfavors the coupling at the terminal position of the conjugated system.…”

Asymmetric nucleophilic substitutions to construct all-carbon quaternary stereocenters under PTC conditions

“…84 Later, R. K. Norris also gave a similar conclusion by examining the reactivity of the p-nitrophenylallyl chloride with lithium 2-nitropropan-2-id, and proposed a radical anion, radical chain substitution reaction with allylic rearrangement (Scheme 1.39). 85 Scheme 1.39 Radical rearrangement in SRN1 process An increase in the steric hindrance at the carbon reacting center of the halide favors an ET route. 86 J. Kowalik reported that when 9-phenylfluorenyl anion reacted with neopentyl-type iodides, the irradiation is necessary for this transformation, but changing the sterically hindered iodidies to MeI, the reaction proceed rapidly even in the dark.…”