Preparation of New N-Heterocyclic Carbene Metal-Alkyne Complexes and Application to a Stereocontrolled Pauson-Khand Reaction

Andrew M. Poulton; Steven D. R. Christie; Ross Fryatt; Sophie H. Dale; Mark R. J. Elsegood; David M. Andrews

doi:10.1055/s-2004-831304

LETTER

Preparation of New N-Heterocyclic Carbene Metal-Alkyne Complexes and Application to a Stereocontrolled Pauson-Khand Reaction

Andrew M. Poulton^a, Steven D. R. Christie*^a, Ross Fryatt^a, Sophie H. Dale^a, Mark R. J. Elsegood^a, David M. Andrews^b,
^a Deptartment of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK
Fax: +44(1509)223925; e-Mail: s.d.christie@lboro.ac.uk;
^b Metabolic and Viral Chemistry, GlaxoSmithKline, Stevenage, SG1 2NY, UK

Abstract

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Abstract

The first reported bimetallic metal-alkyne complexes containing a singly bonded N-heterocyclic carbene ligand have been synthesised and utilised in a stereocontrolled Pauson-Khand reaction.

Key words

alkyne compexes - carbene complexes - asymmetric synthesis

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References

Current address: AstraZeneca, Alderley Park, Macclesfield, Cheshire, SK10 4TF, UK

For some recent reviews of cobalt-alkyne chemistry, see:

<A NAME="RD14604ST-2A">2a</A> Went MJ. Adv. Organomet. Chem. 1997, 41: 69

<A NAME="RD14604ST-2B">2b</A> Welker ME. Curr. Org. Chem. 2001, 5: 785

<A NAME="RD14604ST-3">3</A> Brummond KM. Kent JL. Tetrahedron 2000, 56: 3263

<A NAME="RD14604ST-4">4</A> Fletcher AJ. Christie SDR. J. Chem. Soc., Perkin Trans. 1 2000, 11: 1657

<A NAME="RD14604ST-5">5</A> Teobald B. Tetrahedron 2002, 58: 4133

<A NAME="RD14604ST-6">6</A> D’Agostino MF. Frampton CS. McGlinchey MJ. Organometallics 1990, 9: 2972

<A NAME="RD14604ST-7">7</A> Rutherford DT. Christie SDR. Tetrahedron Lett. 1998, 39: 9805

<A NAME="RD14604ST-8">8</A> Fletcher AJ. Rutherford DT. Christie SDR. Synlett 2000, 1040

<A NAME="RD14604ST-9">9</A> Christie SDR. Davoile RJ. Jones RCF. Tetrahedron Lett. 2002, 43: 7167

<A NAME="RD14604ST-10">10</A> Fletcher AJ. Fryatt R. Rutherford DT. Elsegood MRJ. Christie SDR. Synlett 2001, 1711

<A NAME="RD14604ST-11A">11a</A> Perry MC. Burgess K. Tetrahedron: Asymmetry 2003, 14: 1731

<A NAME="RD14604ST-11B">11b</A> See also: Trnka TM. Grubbs RH. Acc. Chem. Res. 2001, 34: 18

<A NAME="RD14604ST-11C">11c</A> Huang JK. Stevens ED. Nolan SP. Petersen JL. J. Am. Chem. Soc. 1999, 121: 2674

<A NAME="RD14604ST-12">12</A> Herrmann WA. Steffl I. Ziegler ML. Weidenhammer K. Chem. Ber. 1979, 112: 1731

<A NAME="RD14604ST-13">13</A> Herrmann WA. Chem. Ber. 1978, 111: 1077

<A NAME="RD14604ST-14">14</A> Gibson SE. Johnstone C. Loch JA. Steed JW. Stevenazzi A. Organometallics 2003, 22: 5374

<A NAME="RD14604ST-15">15</A> Jafarpour L. Hillier AC. Nolan SP. Organometallics 2002, 21: 442

<A NAME="RD14604ST-16">16</A> Carbery DR. Kerr WJ. Lindsay DM. Scott JS. Watson SP. Tetrahedron Lett. 2000, 41: 3235

<A NAME="RD14604ST-17">17</A> Kennedy AR. Kerr WJ. Lindsay DM. Scott JS. Watson SP. J. Chem. Soc., Perkin Trans. 1 2000, 4366

Determination of the absolute stereochemistry of the IPr substituted complexes and the cyclopentenones is under investigation and will be reported in due course.

We thank the referees for their suggestions for the mechanism of the epimerisation.

Crystal data for 4d: C₃₆H₄₀Co₂N₂O₆, M = 714.56, monoclinic, a = 10.5677(5), b = 17.9251(8), c = 19.7400(8) Å, β = 103.980(2) ° U = 3628.5(3) Å³, T = 150 K, space group P2₁/c (no. 14), Z = 4, µ(MoK_α) = 0.958 mm^-1, 30948 reflections measured, 8656 unique (R _int = 0.017) which were used in all calculations. The final wR2(F ²) = 0.0925 (all data), R1 = 0.0342 [for 7200 data with F ²>2σ(F ²)]. The Co₂ core of the molecule was modelled as disordered with the Co atoms having minor disorder components with an occupancy factor of 8.4(2)%. Crystallographic data have been deposited with the Cambridge Crystallographic Data Centre (CCDC 229596).