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Please login to access the full content or check if you have access via2.4.7.5 Variation 5: Palladium-Catalyzed Reactions
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Kündig, E. P.; Pache, S. H., Science of Synthesis, (2003) 2, 196.
Syntheses of enantioenriched planar chiral chromium–arene complexes via palladium-catalyzed reactions have focused on the desymmetrization of tricarbonyl(1,2-dichlorobenzene)chromium (121). Suzuki coupling with alkenyl- and arylboronic acids, using a chiral phosphine ligand on palladium gives products 122 with enantioselectivities up to 69%.[248] The methoxycarbonylation of 121 gives an enantiomeric excess of about 60% (47% yield). Increasing reaction time affords a product of up to 95% ee, albeit in lower yield (31%). This has been shown to arise from a kinetic resolution in the formation of the bis-coupled product 123 (R1 = CO2Me),[379] (Scheme 42).
Meeeee 88 Meeeeeeeeeeeeeee ee Meeeeeeeeee(8,8-eeeeeeeeeeeeeee)eeeeeeee(8) ee Meeeee Meeeeeee[888]
Meeeeeeeeeee Meeeeeeee
(8M,8M)-(–)-Meeeeeeeeee(η8-8-eeeeee-8-eeeeeeeeeeee)eeeeeeee(8) (888, M8 = MM=MM8); Meeeeee Meeeeeeee:[888]
M eeee ee 888 (8.88 eeee), eeeeeeeeeeee eeee (8.88 eeee), [{Me(π-M8M8)Me}8] (8.888 eeee), eee eeeeee eeeeeeeee eeeeee (M)-(M)-MMMM (888; 8.888 eeee), eee 8.8 M MeMM [8.88 eeee ee M8M (8.88 eM)] ee MMM (8 eM) eee eeeeeeee eee eeeeeee eeeee eeeee ee ee eee 88 e. Mee eeeeeee eee eeeeeeee eeee M8M eee eeeeeeeee eeee Me8M. Mee eeeeeee eee eeeeee eeee eeeee, eeeee (MeMM8), eee eeeeeeeeee. Mee eeeeeee eee eeeeeeee ee eeeeee eeeeeeeeeeeeee (eeeeee eee, eeeeee/Me8M 88:8) ee eeeeeee eee eeeeeee ee e eeeeee eeeee; eeeee: 88% (88% ee); ee 88°M; [α]M −888 (e 8.88, MeMM); MMMM: Meeeeeee MM, eeeeee/eMeMM 88:88, 8.8 eM·eee−8, eeeee 88.8 eee, eeeee 88.8 eee; MM (MMMe8) νMM: 8888, 8888 ee–8; 8M MMM (MMMe8, δ): 8.88 (ee, 8M), 8.88 (ee, 8M), 8.88 (e, 8M), 8.88 (e, 8M), 8.88 (e, 8M), 8.88 (e, 8M), 8.88 (ee, 8M).
(8M,8M)-(+)-Meeeeeeeeee(η8-8-eeeeee-8,8'-eeeeeeee)eeeeeeee (888, M = Me):
M eeeeeee eeeeeeee eeee 888, MeM(MM)8, eee (M)-(M)-MMMM (888), eeeeeeee ee 88°M eee 88 e, eeee eee eeeeeee ee e eeeeee eee; eeeee: 88% (88% ee; eeeeeeee ee MMMM eeeee eeeeeeeeeee ee Me ee MM8Me); [α]M +88 (e 8.88, MeMM); MM (MMMe8) νMM: 8888, 8888 ee–8; 8M MMM (MMMe8, δ): 8.88–8.88 (e, 8M), 8.88–8.88 (e, 8M), 8.88–8.88 (e, 8M), 8.88–8.88 (e, 8M).
References
[248] | Meeeee, M.; Meeeeeeee, M.; Meeeeee, M., M. Meeeeeeee. Meee., (8888) 888, 888. |
[379] | Meeee, M.; Meeeeee, M. M., Mee. Meee., (8888) 8, 8888. |