A micellar alignment effect in the photodimerizations of N-ω-carboxyalkyl-2-pyridones and their 4-alkyl derivatives in micelle or reversed micelle

Nakamura, Y.; Kato, Takeshi; Morita, Yutaka

doi:10.1016/s0040-4039(01)82856-2

Cited by 23 publications

(18 citation statements)

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“…Photodimerization of acenaphthylene and coumarin, the photocycloaddition of acenaphthylene to acryolonitrile, and the photocycloaddition of cyclohexenone to isobutylene are a few examples that illustrate the local concentration effect of micelles (Scheme ). − …”

Section: Micelles As Reaction Mediamentioning

confidence: 99%

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Supramolecular Photochemistry as a Potential Synthetic Tool: Photocycloaddition

2016

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Photochemistry, bearing significant applications in natural and man-made events such as photosynthesis, vision, photolithography, photodynamic therapy, etc., is yet to become a common tool during the synthesis of small molecules in a laboratory. Among other rationale, the inability to influence photochemical reactions with temperature, solvent, additives, etc., dissuades chemists from employing light-initiated reactions as a routine synthetic tool. This review highlights how diverse, highly organized structures such as solvent-free crystals and water-soluble host-guest assemblies can be employed to control and manipulate photoreactions and thereby serve as an efficient tool for chemists, including those interested in synthesis. The efficacy of the media in modifying the excited-state behavior of organic molecules is illustrated with photocycloaddition in general and [2 + 2] photocycloaddition in particular, reactions widely employed in the synthesis of complex natural products as well as highly constrained molecules, as exemplars. The reaction media, highly pertinent in the context of green sustainable chemistry, include solvent-free crystals and solids such as silica, clay, and zeolite and water-soluble hosts that can solubilize and preorganize hydrophobic reactants in water. Since no other reagent would be more sustainable than light and no other medium greener than water, we believe that the supramolecular photochemistry expounded here has a momentous role as a synthetic tool in the future.

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Section: Micelles As Reaction Mediamentioning

confidence: 99%

“…A similar orientation of isophorone, 9-substituted anthracenes, 2-alkoxynaphthalenes, and 2-pyridones in micellar solution can be invoked to explain the high regioselective photodimerization (Schemes , , , and ; Table ). ,,− …”

Section: Micelles As Reaction Mediamentioning

confidence: 99%

Supramolecular Photochemistry as a Potential Synthetic Tool: Photocycloaddition

2016

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“…Preorientation (alignment) effects on photoreactions were first reported in photodimerizations and photoadditions of enones (107,(136)(137)(138)(139)(140). Substrates like were found to form two isomeric dimers on irradiation: head-to-tail and head-tohead photodimers, differing in the direction of the carbonyl group in the products.…”

Section: Preorientation Of Reactantsmentioning

confidence: 97%

Photochemistry in Surfactant Solutions

Bünau¹,

Wolff²

1988

Advances in Photochemistry

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“…5 When this investigation began, cis-selective dimerizations of 2-pyridones had only been observed for reactions performed in micelles. 6 General conditions for trans selectivity have been described, 7 but no equivalent procedure had been developed for cis-selective reactions. Nevertheless, the product mixture formed by 5 indicated that the relative energies of the pro-cis and pro-trans conformations ( Figure 1) leading to [4+4] products 6 and 7 must be nearly identical in energy.…”

Section: Scheme 2 Pyridone [4+4] Cycloadditions Are Generally Trans-smentioning

confidence: 99%

Fusicoccin Synthesis by Intramolecular [4+4] Photocycloaddition of 2-Pyridones: Stereocontrol of the Cycloaddition and Elaboration of the Pentacyclic Product

2004

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F u s i c o c c i n S y n t h e s i s b y I n t r a m o l e c u l a r [ 4 + 4 ] P h o t o c y c l o a d d i t i o n o f 2 -P y r i d o n e sAbstract: Intramolecular photocycloaddition of a three-carbon tethered pyrindinone-pyridone system yields the 5-8-5 ring system of the fusicoccin/ophiobolin/ceroplastol families. The stereoselectivity of the cycloaddition was found to be dependent on nitrogen substitution; N-methylation led to exclusively trans products while an absence of nitrogen substitution resulted in solvent-dependent stereoselectivity. Solvent and concentration effects for this cycloaddition were consistent with a hydrogen-bonded dimer that enforces a pro-cis conformation in nonpolar solvents and at higher concentrations. The cis-isomer, a fusicoccin synthesis intermediate, underwent a Cope rearrangement at ambient temperature but could be trapped efficiently as the mono epoxide, yielding a product with six new stereogenic centers. A four-step transformation of an amide carbonyl to a methyl group was achieved using a carbamoyl group to activate the amide for cleavage. 12 11 7 3 + 2 trans 3 cis 1 hν 56 : 44 ref. 3 4 Downloaded by: Nanyang Technological University NTU. Copyrighted material.

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A micellar alignment effect in the photodimerizations of N-ω-carboxyalkyl-2-pyridones and their 4-alkyl derivatives in micelle or reversed micelle

Cited by 23 publications

References 1 publication

Supramolecular Photochemistry as a Potential Synthetic Tool: Photocycloaddition

Supramolecular Photochemistry as a Potential Synthetic Tool: Photocycloaddition

Photochemistry in Surfactant Solutions

Fusicoccin Synthesis by Intramolecular [4+4] Photocycloaddition of 2-Pyridones: Stereocontrol of the Cycloaddition and Elaboration of the Pentacyclic Product

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