24831-13-8Relevant articles and documents
A C2-chiral bis(amidinium) catalyst for a Diels-Alder reaction constituting the key step of the Quinkert-Dane estrone synthesis
Tsogoeva, Svetlana B.,Duerner, Gerd,Bolte, Michael,Goebel, Michael W.
, p. 1661 - 1664 (2003)
A novel C2-chiral bis(amidinium) salt 12 has been synthesised from 5-(tert-butyl)isophthalic acid. The hydrogenbond-mediated association of dienophiles 3a and 3b with the chiral host molecule 12 accelerates the Diels-Alder reactions with diene 2 by more than three orders of magnitude. In addition, enantioselective formation of the desired adducts is observed under catalysis with 12. Good ratios of 4a(b) + ent-4a(b)/5a(b) + ent-5a(b) from 1:10 to 1:22 were found in all reactions. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.