Nucleophilic addition of organochromium reagents to carbonyl compounds

Abstract

Abstract:One important theme in organic synthesis is to accomplish highly selective transformations under mild conditions, which yield only desirable products. During the past two decades, we have developed several useful tools to achieve this, i.e., organochromium reagents. This review focuses on the following themes: 1) The historical background of organochromium reagents.2) The development of the allylic chromium reagent (Nozaki-Hiyama reaction). 3) Nickel-catalyzed addition of alkenyl-, aryl-, and alkynyl halides to aldehydes (Nozaki-Hiyama-Kishi (NHK) reaction). 4) Wittig-type olefination with geminal dichromium reagents. 5) Representative applications of organochromium reagents to the total syntheses of biologically active compounds.

Asymmetric Catalysis of Nozaki−Hiyama Allylation and Methallylation with A New Tridentate Bis(oxazolinyl)carbazole Ligand

“…Cr(II)-mediated C-C bond-forming reactions originally developed by Nozaki and Hiyama et al 1 have been studied extensively because of their potential utility. 2 These reactions have also been applied to numerous total syntheses of complex natural products due to their high chemoselectivity and excellent compatibility with various functional groups. 2 Although a huge excess of toxic chromium salts had been required to complete these reactions in the early stage, 2 the catalytic redox system reported by Fu ¨rstner et al reduced the quantity of chromium salts, making these reactions more valuable and environmentally benign.…”

Total synthesis of antibiotics: recent achievements, limitations, and perspectives

“…(Moloney, 2004) Several synthesis of oxazolomycin fragments and a total synthesis of neooxazolomycin were reported. (Kende, 1990;Onyango, 2007) In their approach to the oxazolomycin The middle segment of the molecule was prepared from allylamnine in three simple steps and attached to the lactam by Nosaki-Hiyama-Kishi (Takai, 2000) reaction, which in this particular case produced a 3:2 mixture of epimeric alcohols with major diastereomer to be the desired one. The ratio was improved to 4:1 by DMP oxidation/L-Selectride reduction to give after acylation intermediate 84.…”

Thermally Stable Chromium(III) η3-Allyl Complexes. Direct Structural Comparison of Neutral Chromium(II) and Cationic Chromium(III) η3-Allyl Redox Isomers

“…Organochromium chemistry has received considerable attention over the past two decades . Notable among many interesting developments in the area of allylchromium chemistry, chromium(III) η 3 - allyl complexes have been used as precursors in the preparation of olefin polymerization catalysts and are putative intermediates in the stereoselective synthesis of homoallylic alcohols (i.e., the Nozaki−Hiyama−Kishi reaction). 1b-e, Despite such attractive applications, thermally stable chromium(III) complexes of this type are unreported. , Here, however, we report the preparation, isolation, and characterization of several thermally stable cationic chromium(III) η 3 -allyl complexes and provide a direct structural comparison of the unsubstituted cationic complex with the corresponding neutral chromium(II) η 3 - allyl analogue.…”