stable spirocyclic meisenheimer complexes稳定spirocyclic meisenheimer复合物.pdfVIP

Molecules 2008, 13, 1282-1302; DOI: 10.3390/molecule OPEN ACCESS molecules ISSN 1420-3049 /molecules Review Stable Spirocyclic Meisenheimer Complexes Rabih O. Al-Kaysi 1,*, Iluminada Gallardo 2 and Gonzalo Guirado 2,* 1 Department of Basic Sciences, King Saud Bin Abdulaziz University for Health Sciences-National Guard Health Affairs. Building Mail Code 3124. Riyadh 11423. Kingdom of Saudi Arabia; Phone: (966)-5 2 Departament de Química, Universitat Autònoma de Barcelona, 08193-Bellaterra, Barcelona, Spain; Phone: (+) 00 34 93 581 48 82; Fax: (+) 00 34 93 581 29 20 * Authors to whom correspondence should be addressed; E-mails: kaysir@.sa, Gonzalo.Guirado@uab.es Received: 15 May 2008; in revised form: 6 June 2008 / Accepted: 6 June 2008 / Published: 9 June 2008 Abstract: Meisenheimer complexes are important intermediates in Nucleophilic Aromatic Substitution Reactions (SNAr). They are formed by the addition of electron rich species to polynitro aromatic compounds or aromatic compounds with strong electron withdrawing H groups. It is possible to distinguish two types of Meisenheimer or σ-complexes, the σ - complex or σX-complex (also named ipso), depending on the aromatic ring position attacked by the nucleophile (a non-substituted or substituted one, respectively). Special X examples of σ - or ipso-complexes are