Free accessResearch articleFirst published online 1999-9
Preparative-scale HPLC Resolution of Metallacyclic η 3 -Allyltricarbonyliron Complexes and Determination of the Absolute Configuration by X-Ray Crystal Structure Analysis †
Racemates of (η3-allyl)tricarbonyliron lactone complex Fe(CO)3{η1:η3-C(O)XCH2CHCMeCH2} 1a (X = O) and (η3-allyl)tricarbonyliron lactam complex 2a (X = NMe) are resolved on a preparative scale by HPLC on cellulose tris(3,5-dimethylphenyl)carbamate/silica gel RP-8 and the absolute configuration of (-)-2a is determined by X-ray crystal structure analysis.
References
1.
MurdochH. D., Helv. Chim. Acta, 1964, 47, 936.
2.
HeckR. F. and BossC. R., J. Am. Chem. Soc., 1964, 86, 2580.
3.
AumannR., J. Am. Chem. Soc., 1974, 96, 2631;
4.
AumannR., RingH., KrügerC. and GoddardR., Chem. Ber., 1979, 112, 3644.
5.
HodgsonS. T., HollinsheadD. M. and LeyS. V., J. Chem. Soc., Chem. Commun., 1984, 494:
6.
LeyS. V., Philos. Trans. R. Soc. London A, 1988, 326, 633;
7.
BatesR. W., Diéz-MartinD, KerrW. J., KnightJ. G., LeyS. V. and SakellaridisA, Tetrahedron, 1990, 46, 4063;
8.
CarusoM., KnightJ. G. and LeyS. V., Synlett, 1990, 224.
9.
LeyS. V., CoxL. R. and MeekG., Chem. Rev., 1996, 96423;
10.
CoxL. R. and LeyS. V., Chem. Soc. Rev., 199827, 301.
11.
FörtschW., HampelF. and SchobertR., Chem. Ber., 1994, 127, 711;
12.
BöhmerJ., FörtschW., HampelF. and SchobertR., Chem. Ber., 1996, 129, 427;
13.
BöhmerJ., HampelF. and SchobertR., Synthesis, 1997, 661;
14.
BöhmerJ.FörtschW. and SchobertR., Synlett, 1977, 1073;
15.
BöhmerJ. and SchobertR., J. Chem. Res. (S), 1998, 372; for reviews see:
YashimaE., YamamotoC. and OkamotoY., Synlett, 1998, 344;
24.
OkamotoY. and YashimaE., Angew. Chem., 1998, 110, 1072.
25.
Developed by Prof. WernerA., University of Vienna; not commercially available yet.
26.
The capacity factorsk’1 and k'2 reflect the partitioning of the substrate between the phases, the separation factor α is a measure of the separation selectivity; for a definition see: PirkleW. H. and FinnJ. M., in Asymmetric Synthesis, ed. MorrisonJ. D., Academic Press, New York, 1983, vol. 1, p. 87.
27.
For the assignment of the descriptors of the absolute configuration each carbon atom of the allyl unit was considered to be σ-bound to the iron centre.
28.
1H NMR shift analysis proved to be impracticable for the determination of enantiomeric purity of 3a. Treatment of a racemic sample in CDCl3 with Eu(hfc)3 (hfc = heptafluoropropylhydroxymethylene D-camphorate) did not lead to any signal separation.