207912-09-2Relevant academic research and scientific papers
Stereoselectivity in the Birch reduction of 2-furoic acid derivatives
Donohoe, Timothy J.,Helliwell, Madeleine,Stevenson, Clare A.,Ladduwahetty, Tamara
, p. 3071 - 3074 (1998)
The preparation and Birch reduction of chiral 3-methyl-2-furoic acid derivatives is described. Using a Ca symmetrical amine as a chiral auxiliary, very high levels of sterochemical control could be obtained. Moreover, the auxiliary could be removed conveniently by heating in 6M HCl to liberate a carboxylic acid of high enantiomeric purity. The relative stereochemistry of the Birch reduced amides (and therefore the absolute stereochemistry of the corresponding acids) was determined unambiguously from an X-ray crystal structure.
Stereoselective reduction of chiral 2-furoic acid derivatives using group I metals in ammonia
Donohoe, Timothy J.,Calabrese, Andrew A.,Stevenson, Clare A.,Ladduwahetty, Tamara
, p. 3724 - 3731 (2007/10/03)
A series of chiral auxiliaries have been attached to 2-furoic acid and 3-methyl-2-furoic acid. The performance of these auxiliaries in the Birch reduction was assessed and it was found that placing a C-3 methyl group on the heterocycle was essential for good stereoselectivity. Using bis(methoxymethyl)pyrrolidine high levels of diastereoselectivity could be obtained with a range of electrophiles. A model is also presented which explains the sense of stereoselectivity displayed by this auxiliary. After reduction, the auxiliaries could be removed by reaction with acid to furnish dihydrofuran-based carboxylic acids with high enantiomeric excess. The Royal Society of Chemistry 2000.
