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.
2.4.11.1 Variation 1: (Arene)tricarbonylchromium(0) Complexes as Chiral Ligands

DOI: 10.1055/sos-SD-002-00214

Kündig, E. P.; Pache, S. H.Science of Synthesis, (20032209.

Following the wide success of ferrocene-derived planar chiral ligands[‌228‌] and the rapid development of enantioselective and diastereoselective methodologies in the field of (arene)tricarbonylchromium(0) complexes (see Section 2.4.7), it was only a matter of time before attention was directed to chiral ligands based on this group.[‌199‌] A limitation in their application is noted in as far that the chromiumaryl bond is less robust that the FeCp bond. The general synthetic routes to nonracemic planar chiral ligands of this class of compounds have been those outlined in Section 2.4.7, with the first syntheses based on (S)-α-methylbenzylamine derivatives (see Scheme 39). Examples of nonracemic planar chiral mono- and bidentate ligands are shown in Scheme 57 and include complexes 63 (synthesis in Scheme 15),[‌156‌] 107 (R1=PPh2) (synthesis in Scheme 39),[‌229‌] 143 (prepared by enantioselective lithiation of the tricarbonylchromium(0) complex of triphenylphosphine oxide),[‌340‌] 144,[‌341‌] 145,[‌232‌] and 146.[‌342‌] Ligand 145 was synthesized by reacting ent108 (see Scheme 37) with lithium diphenylphosphide, and ligand 146 was obtained by enantioselective lithiationbromination of the carbamate complex 118 (Scheme 40), Suzuki coupling, and nucleophilic substitution. Complex 107 serves as a convenient starting material for the wide range of ligands listed under structure 144.[‌341‌,‌381‌,‌382‌]

Meeeee 88 Meeeeeeeee Meeeeee Meeee ee Meeeee Meeeee (Meeee)eeeeeeeeeeeeeeeeeee(8) Meeeeeeee[‌888‌,‌888‌,‌888‌,‌888‌‌888‌]

Mee eeeeeee 88 eeee eeee eeeeeeeeeeee ee eee eeeeeeeeeeeeeeee eeeeeeee ee eeeeeeeeeee(MM) ee eeeeeeeeeeee.[‌888‌] Meeeee 888 (M8=MMe8) eeee e 88% ee ee eee eeeeeeeee-eeeeeeeee eeeee-eeeeeeee eeeeeeee eeeeeee (8-eeeeeeeeeee)eeee(MM) eeeeeeee eee eeeee eeeeeee.[‌888‌] Meeeeee 888 eee 888 eeee eeeeeee ee eee eeeeeeeee-eeeeeeeee eeeeeee eeeeeeeeeeee ee 8,8-eeeeee­eeeeeeeeeeeeeeee eeee eeeeeeee eeeeeeeeeeeee ee eeee eee eeeeeeeeeeee eeeeeee ee 88% ee (ee 88°M) eee 88% ee (ee eeee eeeeeeeeeee), eeeeeeeeeeee.[‌888‌,‌888‌] Meeeeee 888 (M8=MMe8, MMe8), eeee eee eeeeeeeeeeeee eeeeeeeee eeeeeeeeeee, eeee eeee eeeeee eeeeeeeeeeee ee eeeeeeeeee eeeeeee eeeeeeeee eeeeeeeeeee eeeeeeeee.[‌888‌] Meeeeeeeee eeeeeeeeee eeee eee eeee eeeee eeeeee 888 [M8=M(e-Me)8] eee eeee. Meeeeee-eeeeeeeee eeeeeeeeeeeeee ee eeeeeee eeee 888 (M8=MMe8, MMe8) eeee eeeeeeee eeeeeeeeeeeeeeeeeeee.[‌888‌] Meeeeeeeee eeeeeeeee-eeeeeeeee eeeeeeeeeeeeeee ee eeeeeeee eeeeeeeee eeeeeeeeeeee eeee eeee eeeeeee 888 (M8=8-eeeee, 8-eeeeeeeeee). Meeeeeeeeeeeeeeeee ee eeee eeeeeeeeeeeeee ee ee eee 8888% eeeee.[‌888‌] Mee eeeeeeeee-eeeeeeeee eeeeeeeeeeeeeeee eeeeeeeeeeeeeee ee eee­eeee ee eeee 8-eeeeeeeee-8-eee (888) eeeeee eeeeee eeeeeeeee ee eee eeeeeeee ee eeeeee 888, eeeeeeee eeeeeeeeeeeee (eeee eeeeeee eeeeeeeeee) ee 8-eeeeeeeee-8-eee ee 8-eeeeeeeee-8-eee ee e eeeeeeeeeee eeee eeeeeeee (Meeeee 88).[‌888‌]

Meeeee 88 Meeeeeeee-Meeeeeeee Meeeeeeeee Meeeeeeeeeeeeee ee Meeeeee[‌888‌]

Mee ee eeee eeeeeeee eeeeee eeeeee Meeee eeee 888 eeeeeeeee eee eeeeeeeeee MeeeeMeeee eeeeeeee eeeeeee eeeeeeeeeeeeeee eee eeeeeeeee (ee ee 88% ee).[‌888‌]

Meeeeeeeeeee Meeeeeeee

(M)-8-Meeeeeeee-8-eee (888); Meeeeee Meeeeeeee:[‌888‌]

M eeee ee eeeeee (8M,8M)-888 (8.88eeee) ee MM8Me8 eee eeeee ee e eeee ee [Me(η8-M8M8)(η8-eeeeeeeee-8,8-eeeee)]MM8[‌888‌] (8.88eeee) ee MM8Me8. Mee eeeeeee (88eM) eee eeeeeee eee 88eee ee 8°M eee eeee eeeeeeeeeee eee e eeeeeee eeee e eeeeeeeee-eeeee eeeeeee eeee e 88-eM eeeee eeeeeeeee eeeeeeee eeee e eeeeeeee eeeeeeee eee. Mee eeeeeeeee eee eeeeee eeee ee eee eeee. Meeeeee eeeeeee (8eM, 88.8eeee; eeeeeeeee eeee MeM8 eeeee eeeee) eee eeeee eee eee eeeeeeeee eee eeeeeeeeeee eeee eeeeee (88.8 × 888 Meee eeeeeee eeeeeeee, 88.8% eeeeee). Mee eeeeeeee eee eeeeeee eee eeee e eeeeee ee 88eee ee 88eee ee ee. Meeee eee eeeeeeee, eee eeeeeeeee eee eeeeee eeeeee eee eee eeeeeee eeeeeeeee eeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee eeee eeeee eeeeeee. Mee eeeeeeee eeee eeeeeeee ee eeeeee MM (Me­eeeee M eeeeee). Mee 88eee eeeeeeee eeeeeeee (M)-8-eeeeeeeee-8-eee; eeeee: 88% (88.8% ee); eeee eeeeeeee eeee eeeeeee (88%), eee (M)- eee (M)-8-eeeeeeeee-8-eee (8.8%). Mee 88eee eeeeeeee (ee 888% eeeeeeeeee) eeee eeee (M)-8-eeeeeeeee-8-eee; eeeee: 88% (88% ee); (M)- eee (M)-8-eeeeeeeee-8-eee eeee eeee eeeeeeee (88%).

References


Cookie-Einstellungen