- Efficient copper-catalyzed Michael addition of acrylic derivatives with primary alcohols in the presence of base
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A novel and efficient copper-catalyzed Michael addition of acrylic derivatives with primary alcohols in the presence of base has been developed. The protocol uses readily available acrylic derivatives and primary alcohols as the starting materials, inexpensive CuCl2 as the catalyst, and the corresponding addition products were obtained in moderate to excellent yields.
- Wang, Feng,Yang, Haijun,Fu, Hua,Pei, Zhichao
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supporting information
p. 517 - 519
(2013/02/23)
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- Iridium-catalyzed asymmetric hydrogenation of vinyl ethers
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A carbene-oxazoline catalyst 1 proved to be an effective catalyst for reduction of an enol ether that the literature suggested could not be hydrogenated effectively by P,N-Ir catalysts. Thus, a series of ester and alcohol substrates were hydrogenated using catalyst 1. Good to excellent enantioselectivities and high conversions were obtained.
- Zhu, Ye,Burgess, Kevin
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supporting information; experimental part
p. 979 - 983
(2009/05/30)
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- Conformational Analysis of Oligomers of (R)-3-Hydroxybutanoic Acid in Solutions by 1H NMR Spectroscopy
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Oligomers of (R)-3-hydroxybutanoic acid (3-HB) with different end groups and chain lengths have been prepared as model compounds of bacterial poly[(R)-3-hydroxybutanoate] [P(3-HB)]. They were studied in terms of their conformational behavior generated by rotation about CH2CH bond of 3-HB units in solutions. The conformational behaviors of 3-HB oligomers were investigated in various solvents by analysis of vicinal coupling in the 500-MHz 1H NMR spectra. For all 3-HB oligomers studied in this work, 3-HB units without hydroxy group were found, in every solvent, to adopt similar conformational distributions to those of P(3-HB) polymer backbone in solutions, in which trans and gauche conformers are preferable, while the other gauche conformer is strongly disfavored. On the other hand, 3-HB units adjacent to hydroxy terminal group in 3-HB oligomers show different conformational behaviors relative to those of other 3-HB units. In non-polar organic solvents, only gauche conformer is predominant, due to the formation of an intramolecular hydrogen bond between hydroxy and carbonyl groups, while in polar organic solvents, the conformer distributions are similar to those of 3-HB units without hydroxy groups. In aqueous solution, for 3-HB units adjacent to hydroxy terminal group, the fractions of gauche conformer are still higher than those of trans conformer due to the formation of an intramolecular hydrogen bond.
- Li, Jun,Uzawa, Jun,Doi, Yoshiharu
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p. 1683 - 1689
(2007/10/03)
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- Halogenated Epoxides. 61. Reactions of Selected Chlorooxiranes with Sodium Methoxide: About the Question of Acetylenic and Allenic Epoxides as Intermediates
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Reactions of sodium methoxide with five chlorooxiranes (1, 3, 11, 18, and 19) and with the corresponding isomeric chlorocarbonyl compounds have been examined.In two cases the chlorooxirane and the corresponding chlorocarbonyl compound afforded the same products, however, in different yields.In the other cases the chlorooxiranes and the corresponding chlorocarbonyl compounds gave different products.It is concluded that chlorocarbonyl compounds are not formed to a large extent as intermediates.In the reactions of two chlorooxiranes (18 and 19) with sodium methoxide, acetylenic and allenic epoxides may be invoked as transient intermediates.
- Griesbaum, Karl,Lie, Giu Oan,Keul, Helmut
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p. 679 - 682
(2007/10/02)
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