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Enantioselective Copper-Catalyzed 1,4-Addition of Grignard Reagents to α,β-Unsaturated Carbonyl Compounds

✍ Scribed by Maurus Spescha; Grety Rihs

Publisher
John Wiley and Sons
Year
1993
Tongue
German
Weight
693 KB
Volume
76
Category
Article
ISSN
0018-019X

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✦ Synopsis

The enantioselective copper-catalyzed 1,4-addition of Grignard reagents to a$-unsaturated carbonyl compounds was studied with the following Cu' compounds as catalyst precursor and 1,2 : 5,6-di-0 -isopropylidene-3thio-a -o-glucofuranose (Hsiig) as chiral ligand: CuI, iodo[bis(dibutylsulfide)]copper(I), [Cu(siig)], [Cu(siig)(pp)] (pp = 1,2-bis(diphenylphosphinoethene), and tetrakis[iodo(tributylphosphine)]copper(I). The addition of BuMg halides to cyclohex-2-en-1-one was tested under several reaction conditions. The chemical yields and regioselectivities for this reaction were, in all cases, larger than 90 and 98 YO, respectively, and independent of the experimental conditions. The enantioselectivity was strongly dependent on the reaction conditions and reached a maximum of 60%. Several other substrates were also tested in the above reaction. The X-ray crystal structure for [Cu(siig)(pp)] was determined by X-ray crystallography.

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✍ Motomu Kanai; Yuichi Nakagawa; Kiyoshi Tomioka 📂 Article 📅 2010 🏛 John Wiley and Sons ⚖ 35 KB 👁 2 views

Catalytic Enantioselective Conjugate Addition of Grignard Reagents to Cyclic α,β-Unsaturated Carbonyl Compounds. -The outcome of the title reaction is influenced by many factors such as amount and structure of the chiral phosphine, copper salt, Grignard reagent, as well as the solvent used.