Preferential cis cyclization of 6-hepten-2-yl and related radicals. Example of orbital symmetry control

Beckwith, A. L. J.; Blair, Ian A.; Phillipou, G.

doi:10.1021/ja00812a066

Cited by 92 publications

(30 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Similar results have been obtained with other diallylamine derivatives [ 16,18,19]. The larger amount of the ci s isomer can be explained by application of orbital symmetry considerations [20]. As expected, the polymerization of both monomeric diallylphosphonic acids I and II also gives similar polymer structures containing substituted pyrrolidinium rings (Fig.…”

Section: Acryloylaminomethylphosphonicsupporting

confidence: 85%

Polymeric aminomethylphosphonic acids - 1. Synthesis and properties in solution

Riedelsberger

Jaeger

1998

Designed Monomers and Polymers

View full text Add to dashboard Cite

Abstract-Three water-soluble polyaminomethylphosphonic acids were obtained by radical polymerization in aqueous solution. The corresponding monomers were synthesized by different procedures. A Mannich-type reaction of diallylamine, formaldehyde, and phosphorous acid leads to diallylaminomethylphosphonic acid. Reaction of diallyl formamide and phosphorous acid results in diallylaminomethyldiphosphonic acid. Acryloylaminomethylphosphonic acid was prepared by acylation of aminomethylphosphonic acid. The diallyl compounds polymerize via cyclopolymerization, leading to polymers containing substituted pyrrolidinium rings as units of the macromolecule. Both the monomers and the polymers form zwitterionic structures in aqueous solution within a limited pH range. This was proved by 31 P-, 1H-and 13C-NMR spectroscopy, as well as by FT-IR measurements. The monomers are water-soluble without limitations, but the polymers are insoluble in a pH range near their isoelectric point, which was determined by turbidimetry and viscometry. An improvement of the solubility was achieved after the addition of inorganic salts. As expected, the monomeric and polymeric acryloyl compounds form no zwitterionic structure; both are soluble over the whole pH range investigated.

show abstract

Section: Acryloylaminomethylphosphonicsupporting

confidence: 85%

Polymeric aminomethylphosphonic acids - 1. Synthesis and properties in solution

Riedelsberger

Jaeger

1998

Designed Monomers and Polymers

View full text Add to dashboard Cite

show abstract

“…31 Scheme 8 Syntheses of acyl radicals and two industrially important reactions of peroxyl radicals.…”

Section: Improving Syntheses Based On Radical Chain Reactions (I) Genmentioning

confidence: 99%

The frequently overlooked importance of solvent in free radical syntheses

2011

Self Cite

View full text Add to dashboard Cite

“…Here, the second cyclization [i.e., the cyclization of (8)], is substantially slower [9] than the cyclization of the preceding aryl radical, and in reaction with TTF we isolated [10] a mixture of the two alcohols (9) and (10). Since the second cyclization has a rate constant [9] of about 10 7 s -1 , this implies that, at least with TTF under these conditions, only very rapid cyclizations will be successful. The rate of trapping of carbon radicals can be modulated by changing the structure of the radical-cation [11], but investigations in this area are at an early stage.…”

Section: Oxidative Termination: the Tetrathiafulvalene-mediated Radicmentioning

confidence: 96%

“…To probe whether a slower cyclization could occur, we reacted the substrate (7). Here, the second cyclization [i.e., the cyclization of (8)], is substantially slower [9] than the cyclization of the preceding aryl radical, and in reaction with TTF we isolated [10] a mixture of the two alcohols (9) and (10). Since the second cyclization has a rate constant [9] of about 10 7 s -1 , this implies that, at least with TTF under these conditions, only very rapid cyclizations will be successful.…”

Section: Oxidative Termination: the Tetrathiafulvalene-mediated Radicmentioning

confidence: 99%

Free radicals in synthesis. Clean reagents affording oxidative or reductive termination

Murphy

2000

Pure and Applied Chemistry

View full text Add to dashboard Cite

Neurotoxic organotin reagents currently play a key role in radical chemistry. As a result, this is an important area for development of new clean replacement reactions. The pharmaceutical industry in particular has had to avoid use of radical methodology for the formation of carbon-carbon bonds for this reason. With the current dawn in green chemistry, a host of new clean radical methods is beginning to flourish. Our aim has been to develop new nontoxic methodology for carbon-carbon bond formation by radical chemistry, which would provide either reductive termination (giving a hydrogen atom to the ultimate radical, as happens with tributyltin hydride), or oxidative functionalization, installing a useful polar group at the site of the ultimate radical. Two methods for effecting radical reactions in an environmentally friendly way are presented: (i) The tetrathiafulvalene (TTF)-mediated radicalpolar crossover reaction converts arenediazonium salts to aryl radicals, which have sufficient lifetime to cyclize onto alkenes-the resulting alkyl radicals couple with TTF +• to afford sulfonium salts which, in turn, undergo solvolysis to alcohols, ethers or amides. The method provides the key step in a synthesis of (±)-aspidospermidine. (ii) Hypophosphite salts and hypophosphorous acid, on the other hand, form C-C bonds with reductive termination. These economical reagents afford radicals efficiently, starting from aryl iodides, alkyl bromides, and alkyl iodides, and give very easy separation of products from by-products.

show abstract

Preferential cis cyclization of 6-hepten-2-yl and related radicals. Example of orbital symmetry control

Cited by 92 publications

References 2 publications

Polymeric aminomethylphosphonic acids - 1. Synthesis and properties in solution

Polymeric aminomethylphosphonic acids - 1. Synthesis and properties in solution

The frequently overlooked importance of solvent in free radical syntheses

Free radicals in synthesis. Clean reagents affording oxidative or reductive termination

Contact Info

Product

Resources

About