Cycloadditionen von 3,4‐Dimethoxyfuran an Benzochinone

Hofmann, A.; Wyrsch‐Walraf, Ingeborg; Iten, Peter X.; Eugster, C. H.

doi:10.1002/hlca.19790620718

Cited by 17 publications

(1 citation statement)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Finally, the thioacetate 20 was converted into the rotor 1 in 80 % yield by acidic hydrolysis followed by a mild oxidation with molecular iodine. [31,32] Our comparative model for the rotor 1 was the linear, less hindered rotor 2 (Figure 2), and the synthetic pathway used to prepare this is shown in Scheme 4. Initially, compound 12 was converted in excellent yield (96 %) into compound 21 under Buchwald conditions for Sonogashira coupling of unactivated aryl bromides.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Fluorine‐Containing Molecular Rotors and Their Assembly on Gold Nanoparticles

2010

View full text Add to dashboard Cite

A series of eight rotors containing thiol groups for attachment to gold surfaces and fluorine atoms for solid‐state 19F NMR spectroscopy have been prepared through linear, multistep synthesis. The common rotating part of the rotors (rotator), consisting of a 2,6‐difluorobenzene moiety, is introduced into the rotor structure through an unusual regioselective Sonogashira coupling with 2,6‐difluoro‐1,4‐diiodobenzene. Rotors with different bulky trityl headgroups were prepared, along with their linear, less hindered analogues. These molecular rotors were assembled on gold nanoparticles (AuNPs) and preliminary characterization was performed on these AuNPs in order to study the effects of the sizes of the molecules on the packing behaviour on the AuNP surfaces. As expected, we found that linear molecules adopt more closely packed structures on the surfaces than their bulky analogues. This offers a very promising opportunity to study rotation dynamics at the molecular level by solid‐state NMR spectroscopy.

show abstract

Section: Resultsmentioning

confidence: 99%

Synthesis of Fluorine‐Containing Molecular Rotors and Their Assembly on Gold Nanoparticles

2010

View full text Add to dashboard Cite

show abstract

The Retro–Diels–Alder Reaction PartI.CCDienophiles

Rickborn

1998

Organic Reactions

View full text Add to dashboard Cite

The Diels–Alder (“DA”) reaction is so familiar to organic chemists that the retro‐Diels–Alder or retro‐diene reaction (hereafter “rDA”) requires no conceptual introduction. However, a working definition is needed to indicate the coverage of this review. The intent is to include all reported examples of the general skeletal process excluded in this chapter. Any of the atoms in the starting material (cycloadduct) may be carbon or heteroatom, and substituents on all positions are allowed. In addition, any bond order available to the element in any oxidation state is included, as well as bonding to non‐nearest neighbor atoms (bicyclics, etc.). The volume of literature required separation of this review into two parts. Part I covers all expelled C–C dienophiles, i.e. those reactions that generate a new carbon‐carbon double or triple bond in the dienophile that is formed. Part II, to appear later, covers those expelled dienophiles in which one or both atoms is a heteroatom. Certain specific topics are intentionally omitted. These are: rDA reactions invoked under mass spectral conditions; rDA reactions of polymeric substrates; Electrocyclic processes, some of which are arguably very similar to rDA reactions (these are not addressed unless needed for clarification of an rDA sequence); and a thorough discussion of homo‐rDA reactions. CAS‐Online searches resulted in ca. 1,300 references, of which ca. 900 proved pertinent to the rDA topic as defined and delimited above. Active literature searching was halted in April 1995, but occasional more recent articles are included. Over 2,500 pertinent references were eventually found. Most were obtained by perusal of primary literature (articles) and secondary sources (books and reviews). Computer based search success was limited mainly by the failure of authors or abstractors to key‐word this topic, an especially common occurrence when the expelled dienophile was a simple substance such as N 2 or CO 2 . Overall, approximately 3,500 books, chapters, reviews, articles, and abstracts were consulted in an effort to make this review as comprehensive as possible. This was done with the certainty that some pertinent literature would be missed, tempered by the view that these omissions are probably also lost to any future rational search method. Many secondary sources proved valuable not only for in‐depth discussion of certain rDA reaction types, but also for providing comparisons with related topics. To assist the reader, these secondary sources are referenced (alphabetically by first author within broad subject areas) with a title or brief note on the topic(s) addressed. The first group lists earlier reviews with primary focus on rDA reactions, followed by items of Historical/General Interest, reviews that deal with Experimental Methods, DA reactions (general and specific), reviews of Related Topics (these impinge in more or less significant ways on rDA reactions), and general treatments of Theory and Mechanism.

show abstract