- Catalytic Asymmetric Iterative/Domino Aldehyde Cross-Aldol Reactions for the Rapid and Flexible Synthesis of 1,3-Polyols
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We report here catalytic asymmetric iterative and domino cross-aldol reactions between aldehydes, endowed with a high level of robustness, flexibility, and generality. A Cu(I)-DTBM-SEGPHOS complex catalyzes an asymmetric cross-aldol reaction between acceptor aldehydes and boron enolates derived from donor aldehydes, which are generated through Ir-catalyzed isomerization of allyloxyboronates. The unit process can be repeated using the aldol products in turn as acceptor substrates for the subsequent asymmetric aldol reaction. The donor aldehydes and stereoselectivity can be flexibly switched in a stepwise manner for the double-aldol reaction. Furthermore, asymmetric triple- and quadruple-aldol reactions are possible in one-pot using the appropriate amounts of donors and amine additives, rapidly elongating the carbon skeleton with controlling up to eight stereocenters. The method should be useful for straightforward synthesis of enantiomerically and diastereomerically enriched 1,3-polyols.
- Lin, Luqing,Yamamoto, Kumiko,Mitsunuma, Harunobu,Kanzaki, Yamato,Matsunaga, Shigeki,Kanai, Motomu
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supporting information
p. 15418 - 15421
(2015/12/26)
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- Synthesis and Properties of Some Metal β-Methalloxides
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Metal derivatives of β-methallyl alcohol having the general formulae M3, (M = B and Al); M4, (M = Ge and Ti); M5, (M = Nb and Ta) and BunSn4-n, (n = 1, 2 and 3) have been synthesized by alcohol interchange technique.Germanium tetra-β-methalloxide has been synthesized by the reaction of germanium tetrachloride with β-methallyl alcohol in the presence of dry ammonia as hydrogen chloride acceptor.These newly synthesized β-methalloxides are colourless liquids which can be distilled under reduced pressure.These derivatives have been characterized by elemental analyses, molecular weight determinations and IR as well as PMR spectral data.
- Goel, S. C.,Mehrotra, R. C.
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p. 440 - 442
(2007/10/02)
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