PHANEPHOS-Rh complex

DIPAMP-Rh complex to give the corresponding chiral a-amino acid derivative in over 98% ee. The chiral product has been used for the synthesis of (S)-(-)-ac-romelobic acid [88]. Hydrogenation of a tetrahydropyrazine derivative catalyzed by a PHANEPHOS-Rh complex at -40"C gives an intermediate for the synthesis of Crixivan in 86% ee [82a]. Hydrogenation of another tetrahydropyrazine carboxamide derivative catalyzed by an (R)-BINAP-Rh catalyst leads to the chiral product in 99% ee [89]. 

High catalytic activities have been achieved by the PYRPHOS- [18], PPCP [20], BICHEP- [21], Et-DuPHOS-Rh [19] complexes among others, allowing the reaction with a substrate-to-catalyst molar ratios (S/C) as high as 50,000. With a [2.2]PHANEPHOS-Rh complex, the reaction proceeds even at -45°C [27], Supercritical carbon dioxide, a unique reaction medium, can be used in the DuPHOS and BPE-Rh-catalyzed hydrogenation [43], A highly lipophilic counteranion such as tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BARF) or trifluoromethanesulfonate is used to enhance the solubility of the cationic Rh complexes. Under the most suitable reaction conditions of 102 atm of carbon dioxide, 1 atm of hydrogen, and 22°C, a-amino acid derivatives are produced with up to 99.7% ee. 

Similar observations of reversible formation of solvate dihydrides were made for other BisP -Rh complexes, for the TangPhos-Rh com-plex, and for the PHANEPhos-Rh complex. ... 

A DuPHOS-Rh catalyst reduces both E and Z enamides with a high enantioselectivity even in an alcoholic solvent without E/Z isomerization [57], Notably, (3,(3-disubstituted oc-enamides are also smoothly hydrogenated to (3-branched a-amino acids [58], Sterically less-hindered Me-DuPHOS- and Me-BPE-Rh catalysts provide a high enantioselectivity. The cationic Rh complexes of TRAP [24], BisP [30], and [2.2]PHANEPHOS [27] are also active for hydro-... 

A) Planar Chiral Paracyclophane-Based Bidentate Ligands. As paracaclophane has to some extent similar characteristics as ferrocene, it allows the preparation of bidentate phosphines with planar chirality. First the paracyclophane-based diphosphine ligand, [2.2]Phane-Phos (83, R = Ph), was synthesized by Pye and coworkers.Both Rh- and Ru-complexes of PhanePhos... 

One approach to sertraline via asymmetric hydrogenation was reported by Boulton et al. Enantioselective hydrogenation of the C=C bond in ( )-160 was accomplished in methanol under 120 psi of H2-pressure at room temperature with a planar chiral Rh(I)-(/ )-PhanePhos complex as precatalyst a complete conversion was achieved after 16 hours, and hydrogenated product 161 was obtained with 90% ee (Scheme 29.13). 

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