| Budget Amount *help |
¥3,430,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2007: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2006: ¥2,000,000 (Direct Cost: ¥2,000,000)
|
|---|
| Research Abstract |
Trans influence of the chiral non-C2 symmetrical bidentate ligands containing strong and weak donor heteroatom pairs has proven to be a powerful control element in transition metal-catalyzed enantioselective processes. Among such ligands, thioether-containing phosphine ligands (P, S-mixed Ligand) have recently attracted growing attention because catalysts bearing them have the ability to generate an extra chiral center at the sulfur upon coordination (sulfur chirality) as an additional control element. I previously reported the synthetic study of (R)-2-diphenylphosphino-2'-phenylthio-1,1'-binaphthyl (S-MOP) as the P,S-mixed counterpart of BINAP in which 2-bromo-2'-diphenylphosphinyl-1,1'-binaphthyl 1 is intervened as a key intermediate for the electrophilic sulfenylation in the ligand synthesis. This intermediate would serve as a mono-phosphorus template providing structural diversity of the sulfur subunit of S-MOP ligand, however, its lithiated nucleophile must consider potential race
… More
mization of its axial chirality even at low temperature. In this study, to circumvent the aforementioned drawback, I have developed 2-bromo-2'-phenylthio-1,1'-binaphthyl 2 as the alternative synthetic intermediate, which would also serve as a mono-sulfur template providing an array of the phosphorus subunits of S-MOP ligand. I also applied S-MOP to palladium-catalyzed asymmetric allylic alkylations and Diels-Alder reactions and afforded good to excellent enantioselectivities. In addition, during the course of the study of the development of the palladium catalyst, I have developed a novel biphenylene ring-containing ruthenocene-based phosphine, R-Phos, as a supporting ligand for palladium-catalyzed Suzuki-Miyaura reactions of aryl chlorides with arylboronic acids. In particular, at a 1:3 Pd:R-Phos ratio, substrate combinations even for the construction of highly hindered tetra-ortho-substituted biaryls can be achieved in good to excellent yields with low catalyst loadings in short reaction times. Less
|
