Chiral squaramide-catalyzed asymmetric synthesis of pyranones and pyranonaphthoquinones via cascade reactions of 1,3-dicarbonyls with Morita–Baylis–Hillman acetates of nitroalkenes
作者:Divya K. Nair、Rubem F. S. Menna-Barreto、Eufrânio N. da Silva Júnior、Shaikh M. Mobin、Irishi N. N. Namboothiri
DOI:10.1039/c4cc02279c
日期:——
Cascade reactions of 1,3-dicarbonyls with Morita-Baylis-Hillman acetates of nitroalkenes using a quinine derived chiral squaramide organocatalyst led to the formation of pyranones and pyranonaphthoquinones in good to excellent yields and high diastereo- and enantioselectivities. Representative examples of the reaction scale-up with a much lower catalyst loading without an appreciable loss of selectivities
Highly Diastereo- and Enantioselective Organocatalyzed Michael/Oxa-Michael Sequence: Asymmetric Synthesis of Pyranonaphthoquinone Derivatives
作者:Yong Hwan Kim、Subin Jang、Dae Young Kim
DOI:10.1002/bkcs.11566
日期:2018.10
synthesis of pyranonaphthoquinones via Michael addition and oxo‐Michael cyclization sequence of 2‐hydroxy‐1,4‐naphthoquinone with (E)‐2‐nitroallylic acetates has been developed. The synthetically useful chiral pyranonaphthoquinone derivatives were obtained in moderate to high yields and high enantioselectivities. This approach offers a facile way to prepare chiral pyranonaphthoquinone derivatives with