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DOI: 10.1055/s-2006-949612
A Simple Procedure for the Synthesis of Functionalized 1,3-Butadienes and Cyclopentenones from Fischer Carbene Complexes
Publication History
Publication Date:
24 August 2006 (online)
Abstract
Consecutive treatment of alkenyl carbene complexes with lithium enolates derived from methyl ketones and iodine leads to functionalized 1,3-butadiene derivatives containing both electron-donating and electron-withdrawing groups. Functionalized bicyclic cyclopentenones are easily available by sequential treatment of dihydropyranyl carbene complexes with lithium enolates, iodine, and catalytic amounts of copper(II) triflate.
Key words
carbene complexes - iodine - ketones - organometallic reagents - transition metals
- For selected recent reviews on Fischer carbene complexes, see:
-
1a
Wu Y.-T.Kurahashi T.de Meijere A. J. Organomet. Chem. 2005, 690: 5900 -
1b
Metal Carbenes in Organic Synthesis: Topics in Organometallic Chemistry
Vol. 13:
Dötz KH. Springer; Berlin: 2004. -
1c
Barluenga J.Santamaría J.Tomás M. Chem. Soc. Rev. 2004, 104: 2259 -
1d
Herndon JW. Coord. Chem. Rev. 2004, 248: 3 -
1e
Sierra MA. Chem. Rev. 2000, 100: 3591 -
1f
Zaragoza-Dörwald F. Metal Carbenes in Organic Synthesis Wiley-VCH; New York: 1999. -
1g
Dötz KH.Tomuschat P. Chem. Soc. Rev. 1999, 28: 187 - 2
Fischer EO.Maasböl A. Angew. Chem., Int. Ed. Engl. 1964, 3: 580 - 3
de Meijere A.Schirmer H.Duetsch H. Angew. Chem. Int. Ed. 2000, 39: 3964 -
4a
Barluenga J.Alonso J.Fañanás FJ. Chem. Eur. J. 2005, 11: 4995 -
4b
Barluenga J.Alonso J.Fañanás FJ.Borge J.García-Granda S. Angew. Chem. Int. Ed. 2004, 43: 5510 -
4c
Barluenga J.Alonso J.Fañanás FJ. J. Am. Chem. Soc. 2003, 125: 2610 -
4d
Barluenga J.Alonso J.Rodríguez F.Fañanás FJ. Angew. Chem. Int. Ed. 2000, 39: 2460 -
5a
Barluenga J.Diéguez A.Rodríguez F.Fañanás FJ. J. Am. Chem. Soc. 2002, 124: 9056 -
5b
Barluenga J.Montserrat JM.Flórez J.García-Granda S.Martín E. Chem. Eur. J. 1995, 1: 236 - For iodine oxidations of anions derived from Fischer carbene complexes, see:
-
6a
Fuchibe K.Iwasawa N. Tetrahedron 2000, 56: 4907 -
6b
Iwasawa N.Ochiai T.Maeyama K. J. Org. Chem. 1998, 63: 3164
References and Notes
Alternatively, compound 4 could be formed by the reaction of 5 with iodine through an SE2′ mechanism followed by a γ-elimination.
8The diisopropylamine comes from the generation of lithium enolates 3 with LDA.
9Cyclopentenone Derivatives 8; General Procedure To a THF (10 mL) solution of LDA (0.5 mmol) at -30 °C was added the corresponding ketone (0.5 mmol) to generate enolate 3. After 30 min the solution was cooled to -50 °C and then the carbene complex 2a (0.5 mmol), dissolved in THF (5 mL), was added slowly dropwise. After 10 min I2 (0.5 mmol) was added and the temperature was allowed to rise to r.t. slowly (3 h). The solvents were removed and the residue was filtered through a very short plug of silica (hexane-EtOAc, 2:1). The solvents were removed from the filtrate and the residue was dissolved in the appropriate solvent (Et2O, THF, MeOH, or EtOH; 10 mL). Cu(OTf)2 (0.0125 mmol) was added at 0 °C and then the temperature was allowed to rise to r.t. Silica gel was added (2 g) and the solvents were removed. Purification by column chromatog-raphy gave the corresponding pure cyclopentenone derivative 8.