Reactivity of 2-methylene-1,3-dicarbonyl compounds: catalytic enantioselective Diels–Alder reaction
摘要:
The catalytic enantioselective Diets-Alder reaction of 1,1-dicarbonylethenes 3 with cyclopentadiene in the presence of Ti-TADDOLs, Mg-Ph-box and Mg-Ph-mox complexes was investigated. Although both exo- and enantioselectivity with Ti-TADDOL catalysts were poor, they were much improved using Mg-Ph-box or Mg-Ph-mox complexes as chiral catalysts. Thus, 3 was an efficient two-point binding dienophile and the non-C-2-syrrimetric Ph-mox 8 could be used as a chiral ligand. (C) 2002 Elsevier Science Ltd. All rights reserved.