2024-03-28T18:51:42Zhttps://uvadoc.uva.es/oai/requestoai:uvadoc.uva.es:10324/214492021-06-24T07:42:23Zcom_10324_1187com_10324_931com_10324_894com_10324_28542com_10324_952col_10324_1408col_10324_28543
Tandem Diastereo- and Enantioselective Preparation of Aryl and Alkyl Cyclopropyl Carbinols with Three Adjacent Stereocenters Using Perhydrobenzoxazines and Diethylzinc
Infante Blanco, Rebeca
Nieto Román, Francisco Javier
Andrés Juan, Celia
Química orgánica
Producción Científica
The enantio‐ and diastereoselective one‐pot ethylation/cyclopropanation is efficiently promoted by a chiral perhydrobenzoxazine. The catalytic system tolerates a wide range of di‐ and trisubstituted α,β‐unsaturated aldehydes and has been found to be highly diastereo- and enantioselective. Enals leading to intermediates lacking allylic strain or with either A1,2 or A1,3 strain afford the corresponding syn hydroxycyclopropanes very selectively. While α‐methyl enals are successfully ethylated/cyclopropanated, the presence of bulky substituents at alpha position of the enal constitutes a limitation to the substrate scope. The use of 1,1‐diiodoethane allows the obtention of the corresponding enantioenriched cyclopropylcarbinol, which bears carbon‐substituents at all three positions of the ring, with good enantiocontrol, although moderate diastereoselectivity. A procedure for the asymmetric one‐pot arylation/cyclopropanation of enals is proposed, which involves the use of triarylboroxin, diethylzinc and diiodomethane.
2016-12-05
2016-12-05
2014
info:eu-repo/semantics/article
Organic & Biomolecular Chemistry, 2014, 12, p. 345-354
1477-0520
http://uvadoc.uva.es/handle/10324/21449
10.1039/C3OB41797B
345
12
354
Organic & Biomolecular Chemistry
eng
http://pubs.rsc.org/
info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Attribution-NonCommercial-NoDerivatives 4.0 International
Royal Society of Chemistry