- COMPOSITIONS AND METHODS FOR REDUCTION OF KETONES, ALDEHYDES AND IMINIUMS, AND PRODUCTS PRODUCED THEREBY
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A method of producing an alcohol, comprises reducing an aldehyde or a ketone with a hydridosilatrane. The reducing is carried out with an activator.
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Paragraph 0073-0074
(2018/01/20)
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- Complex Formation between Boric Acid and Triethanolamine in Aqueous Solutions
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The complex formation behavior between boric acid and triethanolamine (TEA, H3L) in aqueous solutions was thoroughly examined by 11BNMR spectroscopy. In chloroform, one 11BNMR signal appeared due to triethanolamine borate (TEA-B, L-B) at -4.6 ppm, whereas in aqueous solutions two signals appeared due to TEA-B and a new boron complex at -5.8 and -9.5 ppm, respectively, in addition to a signal ascribed to boric acid and borate ion. The area ratios between the signals at -5.8 and -9.5 ppm were almost constant regardless of the molar ratios between boric acid and TEA, suggesting that the new complex is a 1: 1 complex between boric acid and TEA. Both complexes were stable in aqueous solutions over the pH range of 6.7 to 10.9. Their chemical shift values were constant and independent of the pH value. This also implies that the new complex has a tetrahedral structure around the boron atom, similar to TEA-B. Based on 1H and 13C NMR spectroscopy and a preliminary examination of complexation between boric acid and aminoalkanols, we have concluded that the new complex (NB, HL-B(OH)) is a 1 : 1 boron to TEA complex with a bicyclo[3,3,0]structure having a boron-nitrogen bond.
- Sonoda, Akinari,Takagi, Norio,Ooi, Kenta,Hirotsu, Takahiro
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p. 161 - 166
(2007/10/03)
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- Organoboranes. LI. Convenient procedures for the recovery of pinanediol in asymmetric synthesis via one-carbon homologation of boronic esters
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Matteson's asymmetric synthesis via a one-carbon homologation of the pinanediol boronic esters with (dichloromethyl)litihium at -100 deg C results in the insertion of a chloromethyl group into the carbon-carbon bond with > 99percent diastereoselectivity.This procedure makes possible the asymmetric synthesis of the chiral moiety, RR'CH*B(OR'')2, providing an alternative route to chiral hydroboration for these valuable chiral intermediates.Unfortunately, this method suffers from the remarkable difficulty encountered in the recovery of the pinanediol chiral auxiliary, making this asymmetric synthesis impractical.Fortunately, a systematic study of the problem has uncovered convenient procedures for the recovery of pinanediol from pianendiol boronate esters
- Brown, Herbert C.,Rangaishenvi, Milind V.
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