Journal
CHEMISTRY-A EUROPEAN JOURNAL
Volume 28, Issue 23, Pages -Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/chem.202200128
Keywords
copper catalyzed; polysubstituted 4H-pyran derivatives; [3+3] annulations
Categories
Funding
- National Key R&D Program of China [2018YFE0126800]
- National Natural Science Foundation of China [21620102003, 21991112, 21831005]
- Shanghai Municipal Education Commission [201701070002E00030]
- Science and Technology Commission of Shanghai Municipality [19JC1430100]
Ask authors/readers for more resources
This study achieved the regioselective [3+3] annulation of alkynyl ketimines with alpha-cyano ketones using Cu(OAc)(2) as the catalyst, resulting in the synthesis of polysubstituted 4H-pyran derivatives with a quaternary CF3-containing center. The strategy demonstrated excellent tolerance towards a wide range of alpha-CF3 alkynyl ketimines and alpha-cyano ketones with various aryl and alkyl substituents. Moreover, asymmetric synthesis of chiral product 3 was attempted and yielded high yields and enantioselectivities. The research has significant implications in the synthesis of polysubstituted 4H-pyran derivatives.
Regioselective [3+3] annulation of alkynyl ketimines with alpha-cyano ketones for the synthesis of polysubstituted 4H-pyran derivatives with a quaternary CF3-containing center has been realized by using Cu(OAc)(2) as the catalyst. The novel strategy tolerates a wide range of alpha-CF3 alkynyl ketimines and alpha-cyano ketones with both aryl and alkyl substitutents. A preliminary asymmetric synthesis of chiral product 3 has been attempted by using copper and chiral thiourea as the cocatalyst with excellent yields (86-99 %) and good enantioselectivities (71-78 % ee). Furthermore, product 3 aa could be obtained on a gram-scale reaction with 75 % yield and 99 % ee after recrystallization. Several products were also transformed readily. Control experiments indicate that the reaction involves a process with a base-catalyzed or chiral thiourea-catalyzed Mannich-type reaction followed by a highly regioselective copper-catalyzed ring-closing reaction on the alkynyl moiety in a 6-endo-dig fashion.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available