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Polyfunctional bis-arylzinc reagents are accessible via a new lithium acetylacetonate-catalyzed iodine-zinc exchange. This protocol tolerates sensitive functional groups (ketones, aldehydes or isothiocyanates) in the aryliodides and allows the formation of highly functionalized zinc reagents. These zinc reagents can be used in a variety of catalyzed and uncatalyzed transformations.

Magnesiumverbindungen spielen eine zentrale Rolle in der praparativen organischen und metallorganischen Chemie. Seit kurzem ermoglicht der Halogen-Magnesium-Austausch den Zugang zu einer Reihe funktionalisierter Grignard-Reagentien. Ester-, Nitril-, Iod- und Iminfunktionen und sogar Nitrogruppen konnen in einer breiten Reihe aromatischer und heterocyclischer Organomagnesiumverbindungen vorhanden sein. Auch hoch funktionalisierte Alkenylmagnesiumspezies konnen auf diese Weise generiert werden. Diese neuen Entwicklungen sowie die Anwendung von Organomagnesiumreagentien in Kreuzkupplungen und Aminierungsreaktionen werden in diesem Aufsatz eingehend beschrieben.

Organomagnesium reagents occupy a central position in synthetic organic and organometallic chemistry. Recently, the halogen-magnesium exchange has considerably extended the range of functionalized Grignard reagents available for synthetic purposes. Functional groups such as esters, nitriles, iodides, imines, or even nitro groups can be present in a wide range of aromatic and heterocyclic organomagnesium reagents. Also various highly functionalized alkenyl magnesium species can be prepared. These recent developments as well as new applications of organomagnesium reagents in cross-coupling reactions and amination reactions will be covered in this Review.

[reaction: see text] Allylic substitution reactions of zinc-copper organometallics on (Z)-allylic pentafluorobenzoates proceed with very high regioselectivity and excellent anti selectivity. The high fidelity in transfer of stereochemical information allowed a short synthesis of (+)-ibuprofen (97% ee).

The iodine–magnesium exchange reaction with i -PrMgCl allows a mild preparation of functionalized arylmagnesium compounds bearing a leaving group in the molecule. With the appropriate transition-metal catalyst (a copper or cobalt salt), cyclization reactions occur leading to five- or six-membered ring systems in good yields.

The reaction of iodophenyl ketones with neo-pentylmagnesium bromide in THF or THF:NMP or THF:DMAC mixtures allows the first preparation of aryl- and heteroarylmagnesium species bearing a ketone. Under appropriate conditions, these new reagents react with a range of electrophiles, leading to polyfunctional products.

The iodine–magnesium exchange reaction with i -PrMgCl allows a mild preparation of functionalized arylmagnesium compounds bearing a leaving group in the molecule. With the appropriate transition-metal catalyst (a copper or cobalt salt), cyclization reactions occur leading to five- or six-membered ring systems in good yields.

1 Introduction 2 Methods of Preparation of Polyfunctional Organozinc Reagents 3 Reactions of Organozinc Reagents 4 Conclusion Keywords: functionalized organozinc compounds; polyfunctional organozinc reagents; polyfunctional organozinc halides; oxidative addition to zinc metal; diorganozinc preparation; boron–zinc exchange; lithium triorganozincates; organozinc reagent reaction

1 Introduction 2 Methods of Preparation of Polyfunctional Organozinc Reagents 3 Reactions of Organozinc Reagents 4 Conclusion Keywords: functionalized organozinc compounds; polyfunctional organozinc reagents; polyfunctional organozinc halides; oxidative addition to zinc metal; diorganozinc preparation; boron–zinc exchange; lithium triorganozincates; organozinc reagent reaction

Background Inhaled perfluorohexan vapor has been shown to improve gas exchange and pulmonary mechanics in oleic acid- and ventilator-induced lung injury. However, in the clinical setting, lung injury frequently occurs in the context of systemic inflammation and consecutive lung injury, which may be induced experimentally by intravenous administration of endotoxin. The authors studied whether vaporized perfluorohexan is efficacious during endotoxin-induced lung injury in domestic pigs. Methods Twenty-two pigs (29 [23, 31] kg body weight [first, third interquartile]; tracheostomy) were anesthetized and mechanically ventilated. In the endotoxin (n = 8) and perfluorohexan groups (n = 7), we administered endotoxin of Escherichia coli 111:B4, 1 mg.kg . h for 1 h and 10 microg.kg.h for 5 h in consecutive order. In the perfluorohexan group, inhalation of the test drug was started 2 h 30 min after the start of the intravenous endotoxin and terminated after 30 min. In a control group (n=7), animals were instrumented and observed over time without further intervention. Oxygenation function was assessed from oxygen partial pressures (Po2, blood gases) and calculated shunt fraction. Respiratory compliance was calculated from airway pressure and tidal volume. Measurements were performed before and every hour during endotoxin infusion. Results After 6 h of endotoxin, gas exchange and pulmonary compliance were deteriorated in the endotoxin group (Pao2: 184 [114, 289] vs. 638 [615, 658] mmHg, pulmonary shunt fraction: 30 [23, 38] vs. 4 [3, 6]%, respiratory compliance: 12 [11, 14] vs. 22 [19, 23] ml/mbar; P < 0.05, endotoxin vs. control). Inhalation of vaporized perfluorohexan did not improve Pao 2 (107 [60, 221] mmHg), pulmonary shunt fraction (32 [26, 58]%), or respiratory compliance (14 [10, 17] ml/mbar) when compared with intravenous endotoxin (not significant, perfluorohexan vs. endotoxin). Conclusions Inhalation of vaporized perfluorohexan does not improve pulmonary gas exchange or respiratory compliance in endotoxin-induced porcine lung injury.

Ethyl 3-(p-cyanophenyl)prolonate R Ethyl 3-iodopropionate 4-Cyanophenylzinc bromide P Ethyl 3-(p-cyanophenyl)propionate Keywords: halogen compounds, iodine compounds; esters, of substituted monobasic acids, halogen esters; replacement reactions, halogen by halogen; sodium iodide; organometallic compounds, zinc; nitriles; halogen compounds, bromine compounds; metalation reactions, zinc; butyllithium; zinc bromide; nitriles; esters, of substituted monobasic acids, miscellaneous; arylation; coupling; metal-catalyzed reactions, nickel