Navigation

0 Hits

  • Previous / Next

You are using Science Of Synthesis as a Guest.
Please login or sign up for a free trial to access the full content.
2.4.7.5 Variation 5: Palladium-Catalyzed Reactions

DOI: 10.1055/sos-SD-002-00214

Kündig, E. P.; Pache, S. H.Science of Synthesis, (20032196.

Syntheses of enantioenriched planar chiral chromiumarene 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 (8.88eeee), eeeeeeeeeeee eeee (8.88eeee), [{Me(π-M8M8)Me}8] (8.888eeee), eee eeeeee eeeeeeeee eeeeee (M)-(M)-MMMM (888; 8.888eeee), eee 8.8M MeMM [8.88eeee ee M8M (8.88eM)] ee MMM (8eM) eee eeeeeeee eee eeeeeee eeeee eeeee ee ee eee 88e. 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, 8.8eM·eee8, eeeee 88.8eee, eeeee 88.8eee; MM (MMMe8) νMM: 8888, 8888ee8; 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 88e, 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, 8888ee8; 8M MMM (MMMe8, δ): 8.888.88 (e, 8M), 8.888.88 (e, 8M), 8.888.88 (e, 8M), 8.888.88 (e, 8M).

References


Cookie-Einstellungen