Elimination Reactions by Sml2 Reduction of Alkyl Halides

2 p-Elimination Reactions by Sml2 Reduction of Alkyl Halides 

Sml2 reduces aldehydes and ketones to the corresponding alcohols. As there are numerous hydride reducing agents for the reduction of aldehydes and ketones, this functional group transformation has not been used widely. In some cases, however, Sml2 can display useful reactivity, stereoselectivity and chemoselec-tivity that more conventional reagents cannot achieve. 

In a detailed kinetic study, Flowers showed that the rate of ketone reduction is directly related to the pof the alcohol proton source used in the reaction and that the proton source must be sufficiently acidic to protonate the ketyl radical anion intermediate 3.11 Interestingly, when H20 is used as a proton 

The ketyl radical anion intermediates can be exploited in carbon-carbon bond-forming reactions. Intermolecular and intramolecular pinacol couplings between the carbonyl groups of ketones and aldehydes are well known (Chapter 5, Section 5.1), as are intermolecular and intramolecular carbonyl-alkene couplings (Chapter 5, Section 5.2). 

2 Generality and Scope of Carbonyl Reduction with Sml2 

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