Borane chemistry synthesis

One such reported example is the synthesis of polypropylene-6-polymethyl-methacrylate (PP-6-PMMA) copolymers utilizing metallocene catalysis and the borane chemistry. In the initial step, PP with chain-end olefinic unsaturations was prepared using metallocene catalysts such as Et(Ind)2ZrCl2/MAO. The unsaturation sites were then hydroborated by 9-borabicyclo[3.3.1]nonane (9-BBN) to produce borane-terminated PP (43) (Fig. 30), which was selectively oxidized and interconverted to a... 

Although carbohydrates are cheap and readily available chiral compounds, their application in stereoselective synthesis was for a long time limited to ex-chiral-pool syntheses [3]. They have been considered too complex compared to other chiral auxiliaries, for example a-pinene in borane-chemistry [4] or BINAP-derivatives in reduction chemistry [5]. However, it has been shown during the past few years that carbohydrates can be successfully applied as stereodifferentiating tools in many different reaction types such as aldol- [6], hydrogenation- [7], carbonyl addition- [8], Michael- [9], Diels-Alder- [10], hetero-Diels-Alder [11], and rearrangement reactions [12]. 

In another application of borane chemistry to steroid synthesis, Bryson developed a synthesis of ( )-estrone methyl ether in which ring C is constructed by hy-droboration-carbonylation of an appropriate l 4-diene (Scheme 25). The basic methodology was demonstrated earlier in a route to 17-desoxyestrone methyl ether. ... 

Also covered is the stabilisation of Ge, Sn, and Pb carbanion equivalents, carbene analogues, cyclotrisilanes and tristannanes. Main Group organometallics in synthesis, applications of Si and Sn in borane chemistry and cross-coupling, disilenes and... 

Chung, T. C. Lu, H. L. Janvikul, W. A novel synthesis of PP-h-PMMA copolymers via metaUocene catalysis and borane chemistry. Polymer 1997, 38,1495-1502. 

The field of borane chemistry continues to expand as evidenced by the extent of published literature in the field during the past years borane lectures [1] included transition metal-promoted coupling of boranes and carboranes [2], the kinetics and mechanisms of the thermolysis and photolysis of binary boranes [3], organoboranes for synthesis [4], and a description of a career in organoborane chemistry [5]. 

Chung TC, Lu li, Janvikul W (1997) A novel synthesis of PP-b-PMMA copolymers via metallocene catalysts and Borane chemistry. Polymer 38 1495... 

Organometallic compounds asymmetric catalysis, 11, 255 chiral auxiliaries, 266 enantioselectivity, 255 see also specific compounds Organozinc chemistry, 260 amino alcohols, 261, 355 chirality amplification, 273 efficiency origins, 273 ligand acceleration, 260 molecular structures, 276 reaction mechanism, 269 transition state models, 264 turnover-limiting step, 271 Orthohydroxylation, naphthol, 230 Osmium, olefin dihydroxylation, 150 Oxametallacycle intermediates, 150, 152 Oxazaborolidines, 134 Oxazoline, 356 Oxidation amines, 155 olefins, 137, 150 reduction, 5 sulfides, 155 Oxidative addition, 5 amine isomerization, 111 hydrogen molecule, 16 Oxidative dimerization, chiral phenols, 287 Oximes, borane reduction, 135 Oxindole alkylation, 338 Oxiranes, enantioselective synthesis, 137, 289, 326, 333, 349, 361 Oxonium polymerization, 332 Oxo process, 162 Oxovanadium complexes, 220 Oxygenation, C—H bonds, 149... 

Further developments are likely as the chemistry of the compounds described above is explored. Moreover, entirely new dimensions may be added. For example, the synthesis of tungsten-alkylidyne complexes with carba-borane ligands with cage structures smaller than the icosahedral C2B9 fragment should result in the isolation of new electronically unsaturated metal cluster and electron-deficient molecules of types as yet unknown. 

H. C. Brown, Boranes in Organic Chemistry, Cornell Univ. Press, Ithaca, New York (1972) G. M. L. Cragg, OrganoboraDes in Organic Synthesis, Marcel Dekker, New York (1973) See also Intra-Science Chemistry Reports (1973)... 

M. Venkat Ram Reddy, born in 1967, received his Ph.D. in organic chemistry from the Indian Institute of Technology, Kanpur, India. Later, he worked with Nobel Laureate Professor Herbert C. Brown and Professor P. V. Ramachandran at the Department of Chemistry, Purdue University, for his postdoctoral studies. He was then appointed as the Assistant Research Scientist in the newly established Herbert C. Brown Center for Borane Research, Purdue University. Since Summer of 2004, he has been an Assistant Professor at the Departments of Pharmacy Practice and Pharmaceutical Sciences and Chemistry and Biochemistry, University of Minnesota Duluth. He has co-authored more than 60 publications and three patents. His research interests include asymmetric organic synthesis and synthesis of small molecules as anticancer agents. 

The synthesis and characterization of the [BsHs]- ion 15,16,17) js one of the most important developments in recent years in the chemistry of pentaborane(9) and its derivatives. Several examples of a new class of pentaborane(9) derivatives have been prepared in which substituents occupy bridging sites 172-175) and significant yields of hexa-borane(lO) 16>17>, hexaborane(12) 17>, or decaborane(14) 16>17> have been obtained from the reaction of B5H8 with B2H6 by careful control of the reaction conditions. 

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