Asymmetric Catalytic Enantio- and Diastereoselective Boron Conjugate Addition Reactions of α-Functionalized α,β-Unsaturated Carbonyl Substrates
作者:Jian-Bo Xie、Siqi Lin、Shuo Qiao、Guigen Li
DOI:10.1021/acs.orglett.6b01998
日期:2016.8.5
established for the asymmetric boron conjugate addition of B2pin2 onto α-functionalized (involving C, N, O, and Cl) α,β-unsaturated carbonyls under mild, neutral conditions involving Cu[(S)-(R)-ppfa]Cl, AgNTf2, and alcohols. The dual additives of AgNTf2 and alcohols were found to play crucial roles for achieving high catalytic activity and enantio- and diastereoselectivity (up to 98% ee and 70:1 dr).
Zur Darstellung α,β-ungesättigter Ketone und ihrer Oxime. 8. Mitt. über ungesättigte Oxime
作者:B. Unterhalt、H. J. Reinhold
DOI:10.1002/ardp.19723050610
日期:——
Aromatische Aldehyde außer Furfural kondensieren im Sauren mit Butanon zu 4‐Aryl‐3‐methyl‐3‐buten‐2‐onen (II). Im Alkalischen erhält man eine Mischung aus 4‐Aryl‐3‐methyl‐3‐buten‐2‐on (II) und 1‐Aryl‐1‐penten‐3‐on (III). Diese Mischung wird oximiert und durch präp. DC aufgetrennt.
除糠醛外的芳香醛在酸中与丁酮缩合形成 4-芳基-3-甲基-3-丁烯-2-酮 (II)。在碱性条件下,得到 4-芳基-3-甲基-3-丁烯-2-酮 (II) 和 1-芳基-1-戊烯-3-酮 (III) 的混合物。该混合物被氧化并通过制备制备。直流分离。
Enantiodivergence in the reduction of α-methyl and α-halomethyl enones by microorganisms
作者:Bruno R.S. de Paula、Dávila S. Zampieri、J. Augusto R. Rodrigues、Paulo J.S. Moran
DOI:10.1016/j.tetasy.2013.07.007
日期:2013.9
Enones (Z)-3-methyl-(Z)-3-chloromethyl- and (Z)-3-bromomethyl-4-R-3-buten-2-one (R = n-pentyl, phenyl, 2'- and 4'-chlorophenyl, 3'- and 4'-nitrophenyl, 4'-methoxyphenyl) were synthesized and subjected to reduction by the microorganisms Saccharomyces cerevisiae and Geotrichum candidum. Whereas the bioreduction of 3-methy-4-R-3-buten-2-ones afforded the corresponding (S)-4-R-3-methybutan-2-ones, the bioreduction of 3-chloromethyl- and 3-bromomethyl-4-R-3-buten-2-ones afforded the corresponding (R)-4-R-3-methybutan-2-ones. (C) 2013 Elsevier Ltd. All rights reserved.