Modified Yamaguchi

Kochetkov and coworkers synthesized erythronolides A (20) and B (21) via a different route [26,27,28]. There have been many reports on the syntheses of erythromycin. Among them, four examples are the Yonemitsu synthesis of erythronolide A (20) [29,30], featuring an extremely efficient macrocyclization (the modified Yamaguchi method) Martin s synthesis of erythromycin B (19) [31,32] Evans synthesis of 6-deoxyerythronolide B [33,34], featuring the aldol-based assemblage of each synthetic segment and the Carreira synthesis of erythronolide A (20), featuring the Mg-mediated cycloadditions of nitrile oxides [35]. 

In a series of remarkable papers, K. Tamao and S. Yamaguchi have shown that the physical properties of triarylboranes and triarylsilanes can be modified using structural changes induced by increasing coordination numbers [74]. In the same way, the tuning of the photophysical properties of PAr3 systems (96-99) (Scheme 27) according to the coordination number of the P-atom has been achieved [75]. 

Fig. 8.2 Resistivity data for some (Cd,Zn)S films. The data from the two Yamaguchi papers were modified to show resistivity values as a function of approximate film composition, rather than solution composition as given in the original papers.

Yamaguchi, S., Hirose, M., Fukushima, S., Hasegawa, R. Ito, N. (1989) Modifieation by eateehol and resoreinol of upper digestive traet eareinogenesis in rats treated with methyl- -amylnitrosamine. Cancer Res., 49, 6015-6018... 

Zwanenburg and coworkers [38] modified the Yamaguchi procedure in the synthesis of the 12-membered macrolide patulolide C 61). Mixed 2,6-chloro-benzoic anhydride, instead of mixed 2,4,6-trichlorobenzoic anhydride, was used. 

The fust important test of this methodology came in Hanessian s investigation of the spiroketal portion of avermectin Bu- This highly convergent approach incorporates all the oxidation levels and functionality required for carbons C(15)-C(28), except for the necessity of alkyne to alkene conversion. The lithium alkynide was prepared at -78 C and then mixed with boron trifluoride etherate under the conditions of Yamaguchi (Scheme 19). (Direct condensation of the lithium salt and lactone lead to substantial amounts of a, -unsaturated lactone.) Addition of the lactone in stoichiometric amounts to the solution of the modified alkynide led to the formation of the desired hemiketal in acceptable yield. Further improvements could be obtained by the recycling of starting material. ... 

Hobson, L.J. Ozu, H. Yamaguchi, M. Hayase, S. Modified Nation 117 as an improved polymer electrolyte membrane for direct methanol fuel cells. J. Electrochem. Soc. 2001, 148, A1185. 

K. Yamaguchi, C. Yoshida, S. Uchida, N. Mizuno, Peroxotungstate immobilized on ionic liquid-modified silica as a heterogeneous epoxidation catalyst with hydrogen peroxide, J. Am. Chem. Soc. 127 (2005) 530. 

J. Kasai, Y. Nakagawa, S. Uchida, K. Yamaguchi, N. Mizuno, I7-1,2-H2SiV2W i,O i, Immobilized on surface-modified SiO2 as a heterogeneous catalyst for liquid-phase oxidation with H2O2, Chem. Eur. J. 12 (2006) 4176. 

T. Sata, T. Yamaguchi, K. Kawamura and K. Matsusaki, Transport numbers of various anions relative to chloride ions in modified anion-exchange membranes during electrodialysis, J. Chem. Soc., Faraday Trans., 1997, 93, 457. 

Taniguchi, J., Iseki, M., Yamaguchi, H., Yasukouchi, K., Surface Enhanced Raman Scattering from bis(4-pyridyl)disulfide- and 4,4 -bipyridine-modified Gold Electrodes , J. Electroanal. Chem. 186 (1985) 299-307. 

Finally, it should be mentioned that Yamaguchi et al. used the SILP concept to immobilize an oxidation catalyst [156]. They found that peroxotungstate [ W(=0)(02)2(H20) 2(/U-0)] can be immobilized on a dihydroimidazolium-based ionic liquid-modified Si02 surface to get an eSicient heterogeneous... 

Yamaguchi Y, Matsuno S., Kagota S., Haginaka J., Kunitomo M. Oxidants in cigarette smoke extract modify low-density lipoprotein in the plasma and facilitate ath-erogenesis in the aorta of Watanabe heritable hyperlipidemic rabbits. 2001 156 109il7. 

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