Asymmetric C-C bond formation via Darzens condensation and Michael addition using monosaccharide-based chiral crown ethers

作者：Bako Peter^*; Rapi Zsolt; Keglevich Gyoergy; Szabo Tamas; Soti Peter L; Vigh Tamas; Gruen Alajos; Holczbauer Tamas

来源：Tetrahedron Letters, 2011, 52(13): 1473-1476.

DOI：10.1016/j.tetlet.2011.01.094

• Darzens condensation
• Michael addition
• Enantioselectivity
• Chiral phase-transfer catalysis
• Crown compounds

Liquid-liquid phase asymmetric Darzens condensations were promoted by D-glucose- and D-mannose-based crown ethers. The corresponding aromatic and heteroaromatic alpha,beta-epoxyketones were obtained with moderate to high enantioselectivities (up to 96%) as well as diastereoselectivities (up to 98:2) under mild reaction conditions. The absolute configurations of several of the epoxyketones were determined by single crystal X-ray analysis. The Michael additions of diethyl acetylaminomalonate to trans-beta-nitroalkenes were carried out in a solid-liquid two-phase system in the presence of a D-glucose-based crown catalyst with up to 99% ee.

• 出版日期2011-3-30