Hydroxylamine catalyzed Nazarov cyclizations of divinyl ketones
摘要:
The first examples of iminium catalyzed Nazarov cyclizations of divinyl ketones are presented. Experiments describing hydroxylamine catalysis of the cyclization of eight alpha-alkoxy divinyl ketones (60-79% yield) and one unactivated divinyl ketone (38% yield) are reported. Phenyl substitution at the beta-position of the divinyl ketone inhibits cyclization, whereas beta-alkyl substituted beta-alkoxy divinyl ketones readily cyclize. (C) 2015 Elsevier Ltd. All rights reserved.
Iodolium salts as halogen-bond donor catalysts in the Nazarov cyclization: the molecular oxygen enigma
作者:Avery J. To、Graham K. Murphy
DOI:10.1039/d2nj02731c
日期:——
Nazarov cyclizations of activated precurosrs are achieved under iodolium catalysis, provided that oxygen is present for catalyst activation and turnover.
An efficient metal-free catalytic protocol for the electrocyclization of alpha-alkoxydienones to cyclopentenones (Nazarov reaction) in near to quantitative yields is described. The key parameters are the use of inexpensive 4-toluenesulfonic acid in 5 mol % at room temperature in acetonitrile or under solvent-free conditions. The versatility of the transformation is demonstrated with unpolarized dienones with good regioselectivities and excellent yields. (c) 2008 Elsevier Ltd. All rights reserved.
New Synthetic Approach to Cyclopenta-Fused Heterocycles Based upon a Mild Nazarov Reaction
作者:Ernesto G. Occhiato、Cristina Prandi、Alessandro Ferrali、Antonio Guarna、Paolo Venturello
DOI:10.1021/jo034939p
日期:2003.12.1
role in forcing the conrotatory process to take place in one sense only: allowing the synthesis of diastereomerically pure compounds to be realized. Because different patterns of substitution on the heterocycle are compatible with the reaction conditions, the methodology developed could be very useful for the synthesis of natural products and biologically active compounds containing cyclopenta-fused O-
Hydroxylamine catalyzed Nazarov cyclizations of divinyl ketones
作者:Joseph Z. Hamilton、Nathaniel T. Kadunce、Michael D. McDonald、Laura Rios、Albert R. Matlin
DOI:10.1016/j.tetlet.2015.10.039
日期:2015.11
The first examples of iminium catalyzed Nazarov cyclizations of divinyl ketones are presented. Experiments describing hydroxylamine catalysis of the cyclization of eight alpha-alkoxy divinyl ketones (60-79% yield) and one unactivated divinyl ketone (38% yield) are reported. Phenyl substitution at the beta-position of the divinyl ketone inhibits cyclization, whereas beta-alkyl substituted beta-alkoxy divinyl ketones readily cyclize. (C) 2015 Elsevier Ltd. All rights reserved.