MeO-dppe

Scheme 5.2 Structure of the ligands used, dppe 1,2-i /s(d iphenyl phosphanyl) ethane o-MeO-dppe 1,2-b/s(di(o-methoxyphenyl) phosphanyl)ethane dcpe 1,2-b/s(dicyclohex-ylphosphanyl)ethane m-MeO-dppe 1,2-bis (di(m-methoxyphenyl) phosphanyl) ethane dppp 1,3 -bis(d iphenyl phosphanyl) propane ...

Fig. 5.4 Dihydrogen pressure drop of the hydrogenation of 1-octene using an /n-s/tM-formed catalyst containing Ni(OAc)2 and the ligand o-MeO-dppe. After 30 and 150 min, fresh 1-octene is added to the reaction mixture and the H2 pressure is reset to 50 bar. (Reproduced from [57])...

The hydroboration of enynes yields either of 1,4-addition and 1,2-addition products, the ratio of which dramatically changes with the phosphine ligand as well as the molar ratio of the ligand to the palladium (Scheme 1-8) [46-51]. ( )-l,3-Dienyl-boronate (24) is selectively obtained in the presence of a chelating bisphosphine such as dppf and dppe. On the other hand, a combination of Pdjldba), with Ph2PC6p5 (1-2 equiv. per palladium) yields allenylboronate (23) as the major product. Thus, a double coordination of two C-C unsaturated bonds of enyne to a coordinate unsaturated catalyst affords 1,4-addition product On the other hand, a monocoordination of an acetylenic triple bond to a rhodium(I)/bisphosphine complex leads to 24. Thus, asymmetric hydroboration of l-buten-3-yne giving (R)-allenyl-boronate with 61% ee is carried out by using a chiral monophosphine (S)-(-)-MeO-MOP (MeO-MOP=2-diphenylphosphino-2 -methoxy-l,l -binaphthyl) [52]. 

In contrast to the formation of linear achiral allylation product on usage of the catalytic system with dppe ligand, employment of the (P)-MeO-MOP ligand gave the branched product in a high regiochemistry and high enantioselectivity. 

Treatment of Mo(N2)2(dppe)2 with nitriles causes displacement of one dinitrogen ligand to give the complexes Mo(N2)CNR(dppe)2 in good yields [R = 4-XC H4, (X = NH2, MeO, Me, Cl, or COMe), 2-MeCftH, Ph, Me or CjHj], and in the cases of R = Me or CjHj the reaction was reversible. The benzylazo complex MoCl(N2COPh)(dppe)2 could be obtained directly from Mo(N2)2(dppe)2 or Mo(N2)-CNR(dppe)2 with an excess of benzylchloride in benzene. ... 

Triarylphosphine oxides are prepared by coupling aryl halides or triflates with diphenylphosphine oxide (36), and they are reduced to triarylphosphine with HSiCls. Selective monophosphination of 2, 2 -bis-triflate of binaphthol (35) with diphenylphosphine oxide occurred to give the optically active phosphine oxide (37) using DPPB or DPPP. No bis-substitution was observed [6,7], The phosphine oxide 37 can be converted to the phosphine by treatment with HSiCls and an amine. Various optically active monodentate phosphines such as MeO-MOP (VI-12) are prepared from 37 via 38. On the other hand, bis-substitution of 35 takes place to afford the bis-phosphine when NiCl2(dppe) is utilized as a catalyst, and the reaction is used for the preparation of BINAP (XV-1) [8]. 

Treatment of the cations [CpMo(CO)(C2H4)(L2)]+ [L2 = dppe, (MeO)2P(CH2)2P(OMe)2] with carbanions [CH(C02)2] at -80°C results in the alkyl complex CpMo CH2CH2CH(C02Et)2KCD)L2. The corresponding reaction with [CpMo(CO)3(C2H4)]+ results in... 

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