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2.
Inorg Chem ; 50(6): 2501-6, 2011 Mar 21.
Article in English | MEDLINE | ID: mdl-21319776

ABSTRACT

The scope of N-atom transfer from the electrophilic ruthenium(VI) nitrido containing polyoxometalate [PW(11)O(39)Ru(VI)N](4-) has been extended to the N-heterocyclic carbene {CH(2)(Mes)N}(2)C and the coupling product {CH(2)(Mes)N}(2)CNH(2)(+) characterized by (1)H NMR and high-resolution mass spectrometry. Because guanidines display many fields of applications ranging from biology to supramolecular chemistry, this could afford an original route to the synthesis of cyclic guanidines. This also enlarges the potential of nitrido complexes in the synthesis of heterocycles, mainly illustrated in the literature through the formation of aziridines through N-atom transfer to alkenes. In the course of the reaction, the ruthenium(III)-containing polyoxometallic intermediate [PW(11)O(39)Ru(III){NC{N(Mes)CH(2)}(2)}](5-) has been thoroughly characterized by continuous-wave and pulsed electron paramagnetic resonance, which nicely confirms the presence of the organic moiety on the polyoxometallic framework, Ru K-edge X-ray absorption near-edge structure, and electrochemistry.


Subject(s)
Guanidines/chemistry , Heterocyclic Compounds/chemistry , Methane/analogs & derivatives , Organometallic Compounds/chemistry , Ruthenium/chemistry , Methane/chemistry , Molecular Structure , Organometallic Compounds/chemical synthesis , Silver/chemistry , Tungsten/chemistry
3.
J Am Chem Soc ; 132(12): 4381-7, 2010 Mar 31.
Article in English | MEDLINE | ID: mdl-20205425

ABSTRACT

A newly designed radical cascade involving N-acyl cyanamides is reported. It builds on aromatic homolytic substitutions as intermediate events and leads to complex heteroaromatic structures via an unprecedented radical migration of a substituent on aryl groups of quinazolinones (hydrogen or alkyl). Mechanistic considerations are detailed, which allowed us to devise fine control over the domino processes. The latter could be predictably stopped at several stages, depending on the reaction conditions. Finally, a surgical introduction of a trifluoromethyl substituent on a quinazolinone was achieved via the reported migration.


Subject(s)
Cyanamide/chemistry , Free Radicals/chemistry , Quinazolinones/chemistry , Biological Products/chemical synthesis , Hydrocarbons, Aromatic/chemistry , Molecular Structure
4.
Chemistry ; 14(4): 1238-52, 2008.
Article in English | MEDLINE | ID: mdl-18046682

ABSTRACT

Amide-iminyl radicals are versatile and efficient intermediates in cascade radical cyclizations of N-acylcyanamides. They are easily trapped by alkenes or (hetero-)aromatic rings and cyclize into a series of new heterocyclic compounds which bear a pyrroloquinazoline moiety. As an illustration of the synthetic importance of these compounds, the total synthesis of the natural antitumor compound luotonin A was achieved through a tin-free radical cascade cyclization process. Not only do amide-iminyl radicals lead to new tetracyclic heterocycles but these nitrogen-centered radical species also react in aromatic homolytic substitutions. Indeed, the amide-iminyl radical moiety unprecedentedly displaces methyl, methoxy, and fluorine radicals from an aromatic carbon atom. This seminal reaction in the field of radical chemistry has been developed experimentally and its mechanism has additionally been investigated by a theoretical study.

6.
Org Lett ; 6(9): 1509-11, 2004 Apr 29.
Article in English | MEDLINE | ID: mdl-15101779

ABSTRACT

[reaction: see text] Various ene-tosylynamides react with platinum(II) chloride and lead to bicyclic nitrogenated heterocycles. This unprecedented and easily operated process can be coupled with a hydrolysis of the intermediate cyclic tosylenamides in a one-pot transformation, which provides cyclobutanones.

7.
Org Lett ; 5(26): 5095-7, 2003 Dec 25.
Article in English | MEDLINE | ID: mdl-14682773

ABSTRACT

A radical cascade involving a 5-exo-dig cyclization followed by a 6-endo-trig radical trapping transforms ynamides into heterogeneous polycyclic compounds in good yields. This leads interestingly to the formation of isoindols, isoindolinones, and pyridoisoindolones. [reaction: see text]

8.
Curr Opin Drug Discov Devel ; 5(6): 928-36, 2002 Nov.
Article in English | MEDLINE | ID: mdl-12478723

ABSTRACT

This short review presents a selection of metal-mediated and radical polycyclizations reported during the past two years. Palladium-catalyzed domino processes, cobalt-mediated cycloadditions and Pauson-Khand reactions catalyzed by rhodium are described. Ruthenium and platinum are shown as powerful metal catalysts in cyclizations, ring-closing metathesis and cycloisomerizations. Finally, recent examples of radical cascades, and their synthetic applications, are selected for their ability to build polycyclic compounds.


Subject(s)
Metals/metabolism , Polycyclic Compounds/metabolism , Technology, Pharmaceutical/methods , Animals , Catalysis/drug effects , Free Radicals/chemistry , Free Radicals/metabolism , Humans , Metals/chemistry , Polycyclic Compounds/chemistry , Stereoisomerism
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