Solvias MeOBIPHEP Ligands

Introduction
State-of-the-art atropisomeric MeOBIPHEP ligands, also referred to as MeO-BIPHEP, originally developed by Roche, have an extraordinarily broad performance profile for many synthetic applications due to their modular ligand design. In many respects, the catalytic profile of the MeOBIPHEP ligands is rather similar to that of other atropisomeric diphosphines such as BINAP and its many analogs.1–4 The nature of the PR2 group strongly influences the catalytic performance of the metal complexes, and the ligands available in research quantities from Sigma-Aldrich represent examples with different steric bulk.

References

1. Blaser, H.-U. et al. Chimica Oggi Supplement Catalytic Applications 2007, 25(2), 8.
2. Blaser, H.-U. et al. Acc. Chem. Res. 2007, 40, 1240.
3. Tang, W.; Zhang, X. Chem. Rev. 2003, 103, 3029.
4. Schmid, R. et al. Pure Appl. Chem. 1996, 68, 131.

Representative Applications

Hydrogenation of α- and β-functionalized ketones
Ru-MeOBIPHEP complexes are highly effective for the hydrogenation of α- and β-functionalized ketones. Studied by Genêt and co-workers, a range of alkyl- and aryl β-keto esters and β-keto sulfones could be reduced in very high enantioselectivities using 29510 (1st eq.). A p-chlorophenylglyoxylic acid derivative could be successfully enantioselectively reduced on bench scale using 29510 to give the corresponding mandelic acid amide depicted with 93% ee and with a TON of ca. 4000 h-1 (2nd eq.). Genêt also described the synthesis of a chiral 2-chloro-1,3-dicarbonyl compound via dynamic kinetic resolution using Ru-MeOBIPHEP 29510 (3rd eq.). Finally, the Hamada group successfully applied Ir-MeOBIPHEP catalysts 29510 in the highly diastereo- and enantioselective reduction of β-hydroxy-α-amino esters (4th eq.).

Scheme 1

References

1. Ratovelomanana-Vidal, V. et al. Adv. Synth. Catal. 2003, 345, 261.
2. Blanc, D. et al. J. Organomet. Chem. 2000, 603, 128.
3. Bertus, P. et al. Tetrahedron: Asymmetry 1999, 10, 1369.
4. Cederbaum, F. et al. Adv. Synth. Catal. 2004, 346, 842.
5. Mordant, C. et al. Synthesis 2003, 2405.
6. Makino, K. et al. Org. Lett. 2006, 8, 4573.

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Hydrogenation of allylic alcohols and α,β-unsaturated esters
MeOBIPHEP ligands are used in an impressive number of industrial hydrogenation processes on pilot scale developed by Roche. Not only enantioselectivities are excellent, but also TON and TOFs are on an impressively high level for various substrates.

Scheme 2

References

1. Schmid, R.; Scalone M. Comprehensive Asymmetric Catalysis; Jacobsen, E. N., Yamamoto, H., Pfaltz, A., Eds.; Springer: Berlin, 1999; p 1439.
2. Crameri, Y. et al. Chimia 1997, 51, 303.
3. Netscher, T. et al. Large Scale Asymmetric Catalysis; Blaser, H.-U., Schmidt, E., Eds.; Wiley-VCH: Weinheim, 2004; p 71.

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Hydrogenation of heteroarenes
Wang et al. described the enantioselective hydrogenation of quinoline derivatives with an Ir-MeOBIPHEP 29510 catalyst. This method provides an efficient access to a variety of optically active tetrahydroquinolines with up to 96% ee. This methodology has been applied to the asymmetric synthesis of three naturally occurring alkaloids angustureine, galipinine, and cuspareine.

Scheme 3

Reference
Wang, W.-B. et al. J. Am. Chem. Soc. 2003, 125, 10536.

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C–C coupling reactions
The Krische group reported on the enantioselective Rh-catalyzed reductive coupling of acetylene to aldehydes to α-ketoesters using 29510 to yield the corresponding diene alcohols in good yields and enantioselectivities (1st eq.). The Wiedenhoefer group reported on the intramolecular asymmetric hydroarylation of 2-(4-pentenyl)indoles in moderate to good yield with up to 90% ee catalyzed by a 1:1 mixture of dichloro platinum complex and (S)-3,5-t-Bu-4-MeO-MeOBIPHEP 29511 (2nd eq.). Pregosin and co-workers reported a dramatic improvement of enantioselection in the Pd-catalyzed Heck reaction of aryl triflates to 2-substituted dihydrofuranes when using (R)-3,5-t-Bu-MeOBIPHEP 29524 (3rd eq.).

Scheme 4

References

1. Kong, J. R.; Krische, M. J. J. Am. Chem. Soc. 2006, 128, 16040.
2. Han, X.; Widenhoefer, R. A. Org. Lett. 2006, 8, 3801.
3. Tschoerner, M. et al. Organometallics 1999, 18, 670.

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Product Information

Product No.	Product Name	Structure	Add to Cart
29510	(R)-(+)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis(diphenylphosphine)
29511	(S)-(-)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis(diphenylphosphine)
29512	(R)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(3,5-di-tert-butyl-4-methoxyphenyl)phosphine]
29513	(S)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(3,5-di-tert-butyl-4-methoxyphenyl)phosphine]
29514	(R)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis(di-2-furylphosphine)
29515	(S)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis(di-2-furylphosphine)
29516	(R)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(3,5-dimethylphenyl)phosphine]
29517	(S)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(3,5-dimethylphenyl)phosphine]
29518	(R)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis(diisopropylphosphine)
29519	(S)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis(diisopropylphosphine)
29520	(R)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(4-methylphenyl)phosphine]
29521	(S)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(4-methylphenyl)phosphine]
29524	(R)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(3,5-di-tert-butylphenyl)phosphine]
29525	(S)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(3,5-di-tert-butylphenyl)phosphine]
29526	(R)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(3,4,5-trimethoxyphenyl)phosphine]
29527	(S)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis[bis(3,4,5-trimethoxyphenyl)phosphine]
29528	(R)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis{bis[3,5-diisopropyl-4-(dimethylamino)phenyl]phosphine}
29529	(S)-(6,6'-Dimethoxybiphenyl-2,2'-diyl)bis{bis[3,5-diisopropyl-4-(dimethylamino)phenyl]phosphine}

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