Effective synthesis of 2,5-disubstituted terahydrofurans from glycerol by catalytic alkylation of ketones

27 Oct 2011

Scientists from Germany have developed an efficient diastereoselective synthesis of 2,5-disubstituted tetrahydrofurans in three steps.

Magnus Rueping and Vilas Phapale used [IrCl(cod)]2 to catalyze the α-alkylation of substituted acetophenones with solketal (obtained from the protection of glycerol by actenone) as the hydrogen donor. This route avoids the use of electrophilic alkylating agents like alkyl halides and as a result does not suffer from drawbacks such as salt or by-product formation. The resulting products could then undergo reduction with NaBH4 to give the corresponding secondary alcohols, before subsequent acetyl deprotection and cyclisation by FeCl3 to give 2,5-disubstituted tetrahydrofurans.

Furthermore, a one-pot, three-step version of this procedure could be performed which does not require chomatographic purification of any of the intermediates.

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Effective synthesis of 2,5-disubstituted tetrahydrofurans from glycerol by catalytic alkylation of ketones, Magnus Rueping and Vilas B. Phapale, Green Chem., 2011, DOI: 10.1039/C1GC15764G