BINAP ligand derivatives

Furukawa and co-workers (368,369) succeeded in applying the softer dicationic Pd-BINAP 260 as a catalyst for the 1,3-dipolar cycloaddition between 225 and 241a (Scheme 12.82). In most cases, mixtures of endo-243 and exo-243 were obtained, however, enantioselectives of up to 93% ee were observed for reactions of some derivatives of 225. A transition state structure has been proposed to account for the high selectivities obtained for some of the substrates (368). In the structure shown in Scheme 12.82, the two phosphorous atoms of the Tol-BINAP ligand and the two carbonyl oxygens of the crotonoyl oxazolidinone are arranged in a square-planar fashion around the palladium center. This leaves the ii-face of the alkene available for the cycloaddition reaction, while the re-face is shielded by one of the Tol-BINAP tolyl groups. 

The second key step is a radical eyclization utilised for creation of the tricyclic system 16. The stereochemistry of the resulting fKwly introduced stereogenic center is established entirely by substrate control, and is thus also derived indirectly from the BINAP ligand. 

The widely studied Ru(BINAP)(OAc)2 catalyst is derived from [Ru(BINAP)Cl2]2(NEt3) which is in turn obtained from reacting [Ru(COD)Cl2]n with BINAP ligand in the presence of excess triethylamine 12,13). 

Aza Diels-Alder reactions. The p-tol-BINAP ligand is used to promote asymmetric condensation between the IV-tosyl derivative of ethyl glyoxylate and Danishefsky s diene at -78°. 

Rhodium complexes containing chiral organophosphorus ligands are of interest in view of their potential use as catalysts. With this application in mind, Viau et al. have prepared and characterised complex (148) (Scheme 30), which contains an ylide derivative (147) of the well-known R-BINAP ligand. ... 

Nonionic, asymmetric polyoxy-1,2- and -1,4-diphosphines, analogs of Prophos and DIOP have been prepared [23a,b], as well as a chiral polyether phosphite ligand derived from (S)-binaphthol [23c] and PEG-BINAP [23d] through polycondensation of 5,5 -diamino-BINAP, polyethylene glycol, and terephthalic chloride. 

Rhodium and iridium catalysts incorporating bisphosphine ligands such as BINAP and derivatives have also been shown to be effective in the asymmetric Pauson—Khand reaction of 1,6-enynes, and some high ees have been obtained with substrates incorporating heteroatoms. As an example, the allylpropargylamine (8.243) is converted into the bicychc product (8.244) with high ee in the presence of an iridium/ToIBINAP catalyst. It has been shown that, in some cases, aldehydes... 

Compared to very extensive studies on Heck reactions, examples of successful asymmetric Heck reactions (abbreviated to AHR in this section) are rather limited, showing that AHRs are not easy to carry out, and careful tuning of conditions is crucial. Most of the HRs proceed by using monodentate ligands. On the other hand, chiral bidentate ligands are mainly required for AHRs. This may be a reason for the difficulty in achieving efficient AHRs. The ligands most extensively used are BINAP, its derivatives, and phosphinooxazolines [116]. 

Recently, Ghosh and coworkers have reported a Ru(II) catalyst derived from (S,S)-l,2-diphenylenediamine and chiral (S)-BINAP ligand (Scheme 11.3) [54]. The catalyst was supported or tethered on MCM-41 or MCM-48 zeolite. 

Since the BINAP ligand is optically active, the catalytic reaction is enantiomericaUy selective. The rigidity of this phosphine ligand derives from the connectedness of the phosphine groups. 

Chlorination of JV-acetyloxazolidinones with a preformed nickel catalyst derived from the BINAP ligand. 

Hadzovic, A. Song, D. MacLaughlin, C. M. Morris, R. H. A mechanism displaying autocatalysis The hydrogenation of acetophenone catalyzed by RuH(S-binap)(app) where app is the amido ligand derived from 2-Amino-2-(2-pyridyl)propane. Organometallics 2007,26,5987-5999. 

Kobayashi and co-workers successfully achieved the asymmetric 1,3-dipolar cycloaddition reaction of azomethine imines with terminal alkynes catalyzed by CuHMDS and DIP-BINAP ligand to provide N,N-bicyclic pyrazolidinone derivatives in high yields with exclusive regioselectivity and excellent enantioselectivity (Scheme 26) [46]. Mechanistic studies elucidated a stepwise reaction pathway and revealed that the steric character of the ligand determines the regioselectivity. Arai and co-workers applied chiral bis(imidazolidine)pyridine-CuOAc complex to the [3+2]cycloaddition of azomethine imines with propiolates for the construction of bicyclic pyrazolo[l,2-a]pyrazolone derivatives with up to 74% ee [47]. 

Figure 4.19 Dendritic BINAP ligands for the Ir-catalyzed asymmetric hydrogenation of quinoline derivatives.

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