Technical Notes:
1.Catalyst for asymmetric formal 2 + 2-cycloadditions.
2.Catalyst for highly enantioselective synthesis of chiral 7-ring O- and N-heterocycles via nitro- MichaeI- cyclization tandem reaction.
References:
1.J. Am. Chem. Soc. 2012, 134, 2543. 2.Chem. Commun., 2013, 49, 11665 .