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
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
Removing the superfluous: a supported squaramide catalyst with a minimalistic linker applied to the enantioselective flow synthesis of pyranonaphthoquinones
作者:Laura Osorio-Planes、Carles Rodríguez-Escrich、Miquel A. Pericàs
DOI:10.1039/c6cy00473c
日期:——
A continuousflow setup has been implemented for the enantioselectiveproduction of a library of pyranonaphthoquinones. This was possible through a sequential two-step process involving a squaramide-catalyzed Michael reaction and oxa-Michael cyclization. A key factor for the success of this methodology was the development of a new, cost-effective polystyrene-supported squaramide.