scholarly journals Sequential Norrish Type II Photoelimination and Intramolecular Aldol Cyclization of α-Diketones: Synthesis of Polyhydroxylated Cyclopentitols by Ring Contraction of Hexopyranose Carbohydrate Derivatives

2013 ◽  
Vol 19 (31) ◽  
pp. 10312-10333 ◽  
Author(s):  
Dimitri Alvarez-Dorta ◽  
Elisa I. León ◽  
Alan R. Kennedy ◽  
Angeles Martín ◽  
Inés Pérez-Martín ◽  
...  
Keyword(s):  
Type Ii ◽  
Ring Contraction ◽  
Norrish Type ◽  
Aldol Cyclization

ChemInform Abstract: Sequential Norrish Type II Photoelimination and Intramolecular Aldol Cyclization of 1,2-Diketones in Carbohydrate Systems: Stereoselective Synthesis of Cyclopentitols.

ChemInform ◽  
2009 ◽  
Vol 40 (9) ◽  
Author(s):  
Dimitri Alvarez-Dorta ◽  
Elisa I. Leon ◽  
Alan R. Kennedy ◽  
Concepcion Riesco-Fagundo ◽  
Ernesto Suarez
Keyword(s):  
Stereoselective Synthesis ◽  
Type Ii ◽  
Norrish Type ◽  
Aldol Cyclization

scholarly journals Photo-mediated ring contraction of saturated heterocycles

Science ◽  
2021 ◽  
pp. eabi7183
Author(s):  
Justin Jurczyk ◽  
Michaelyn C. Lux ◽  
Donovon Adpressa ◽  
Sojung F. Kim ◽  
Yu-hong Lam ◽  
...  
Keyword(s):  
Chemical Space ◽  
Type Ii ◽  
Specific Chemical ◽  
Ring Contraction ◽  
Bioactive Natural Products ◽  
Compound Libraries ◽  
Norrish Type ◽  
And Function ◽  
Core Framework ◽  
Saturated Heterocycles

Saturated heterocycles are found in numerous therapeutics as well as bioactive natural products and are abundant in many medicinal and agrochemical compound libraries. To access new chemical space and function, many methods for functionalization on the periphery of these structures have been developed. Comparatively fewer methods are known for restructuring their core framework. Herein, we describe a visible light-mediated ring contraction of α-acylated saturated heterocycles. This unconventional transformation is orthogonal to traditional ring contractions, challenging the paradigm for diversification of heterocycles including piperidine, morpholine, thiane, tetrahydropyran, and tetrahydroisoquinoline derivatives. The success of this Norrish Type II variant rests on reactivity differences between photoreactive ketone groups in specific chemical environments. This strategy was applied to late-stage remodeling of pharmaceutical derivatives, peptides, and sugars.

Sequential Norrish Type II Photoelimination and Intramolecular Aldol Cyclization of 1,2-Diketones in Carbohydrate Systems: Stereoselective Synthesis of Cyclopentitols

2008 ◽  
Vol 120 (46) ◽  
pp. 9049-9051 ◽  
Author(s):  
Dimitri Álvarez-Dorta ◽  
Elisa I. León ◽  
Alan R. Kennedy ◽  
Concepción Riesco-Fagundo ◽  
Ernesto Suárez
Keyword(s):  
Stereoselective Synthesis ◽  
Type Ii ◽  
Norrish Type ◽  
Aldol Cyclization

Sequential Norrish Type II Photoelimination and Intramolecular Aldol Cyclization of 1,2-Diketones in Carbohydrate Systems: Stereoselective Synthesis of Cyclopentitols

2008 ◽  
Vol 47 (46) ◽  
pp. 8917-8919 ◽  
Author(s):  
Dimitri Álvarez-Dorta ◽  
Elisa I. León ◽  
Alan R. Kennedy ◽  
Concepción Riesco-Fagundo ◽  
Ernesto Suárez
Keyword(s):  
Stereoselective Synthesis ◽  
Type Ii ◽  
Norrish Type ◽  
Aldol Cyclization

Temperature Dependent Solvent Effects in Photochemistry of 1-Phenylpentan-1-ones

1999 ◽  
Vol 64 (12) ◽  
pp. 2007-2018 ◽  
Author(s):  
Petr Klán ◽  
Jaromír Literák
Keyword(s):  
Solvent Effects ◽  
Solvent Polarity ◽  
Structure Change ◽  
Type Ii ◽  
Temperature Dependent ◽  
Methyl Derivative ◽  
Methyl Substitution ◽  
Weak Bases ◽  
Norrish Type ◽  
Small Structure

Temperature dependent solvent effects have been investigated on the Norrish Type II reaction of 1-phenylpentan-1-one and its p-methyl derivative. Efficiencies of the photoreaction were studied in terms of solvent polarity and base addition as a function of temperature. Such a small structure change as the p-methyl substitution in 1-phenylpentan-1-one altered the temperature dependent photoreactivity in presence of weak bases. The experimental results suggest that the hydrogen bonding between the Type II biradical intermediate OH group and the solvent is weaker for 1-(4-methylphenyl)pentan-1-one than that for 1-phenylpentan-1-one at 20 °C but the interactions probably vanish in both cases at 80 °C.

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