Pinacolic Coupling Reactions
Both aldehydes and ketones are coupled in the presence of SmI2 to give pinacol. The reaction is carried out in the absence of proton source. Intramolecular reactions proceed with excellent diastereoselectivity (Scheme 13).
Scheme 13
Radical Addition to Alkenes and Alkynes
SmI2 can mediate the cyclization of aryl radicals onto alkene and alkyne acceptors to give an excellent route to the synthesis of heterocycles (Scheme 14). This protocol afford effective route to construct more highly functionalized frameworks through sequential radical cyclization.
Scheme 14
Reduction Reactions
SmI2 reduces alkyl halides to give hydrocarbons in the presence of proton source (Scheme 15). The reactivity order of alkyl halides is R-I > R-Br > R-Cl. This method provides effective route to reduce the substrates in which the halide is resistant to reduction by hydride reducing agents (Scheme 16).
Scheme 15
Scheme 16
Under similar conditions, the reduction of α -heterosubstituted carbonyl compounds can be accomplished. A wide range of substrates proceeds reaction to give unsubstituted ketones under mild conditions (Scheme 17). These conditions can also be applied for the reductive cleavage of α -alkoxy ketones to give the corresponding β -hydroxy carbonyl compounds (Scheme 18).
Scheme 17
Scheme 18
SmI2 can also be used for the reduction of sulfoxide and sulfones to give sulfides under mild conditions (Scheme 19).
Scheme 19