Asymmetric transfer hydrogenation of α,β-unsaturated, α-tosyloxy and α-substituted ketones
作者:Philip Peach、David J. Cross、Jennifer A. Kenny、Inderjit Mann、Ian Houson、Lynne Campbell、Tim Walsgrove、Martin Wills
DOI:10.1016/j.tet.2005.11.036
日期:2006.2
Asymmetric transferhydrogenation of cyclic and acyclic α,β-unsaturatedketones catalysed by η6-p-cymene/ruthenium(II) and η5-pentamethylcyclopentadienyl/rhodium(III) complexes have been investigated. Cyclicα,β-unsaturatedketones appeared to be more suitable substrates for the synthesis of enantiomerically pure allylic alcohols than do acyclic α,β-unsaturatedketones. A proposed mechanism for the
环状和无环α的不对称转移氢化,β不饱和酮由η催化6 - p -cymene /钌(II)和η 5 -五甲基/铑(III)络合物进行了研究。环状α,β-不饱和酮似乎比无环α,β-不饱和酮更适合用于合成对映体纯的烯丙基醇。讨论了一种由α-甲苯磺酰氧基和卤素取代的苯乙酮形成4-苯基-[1,3]-二氧戊环-2-酮的机理。提出了进一步研究减少α-甲苯磺酰氧基苯乙酮范围和α-取代酮的动态动力学拆分的结果。
Mild and Expedient Asymmetric Reductions of α,β-Unsaturated Alkenyl and Alkynyl Ketones by TarB-NO<sub>2</sub> and Mechanistic Investigations of Ketone Reduction
作者:Scott Eagon、Cassandra DeLieto、William J. McDonald、Dustin Haddenham、Jaime Saavedra、Jinsoo Kim、Bakthan Singaram
DOI:10.1021/jo101530f
日期:2010.11.19
yields up to 99%. In the case of α,β-unsaturated alkenyl ketones, α-substituted cycloalkenones were reduced with up to 99% ee, while more substituted and acyclic derivatives exhibited lower induction. For α,β-ynones, it was found that highly branched aliphatic ynones were reduced with optimal induction up to 90% ee, while reduction of aromatic and linear aliphatic derivatives resulted in more modest enantioselectivity
Are bis(pyridine)iodine(<scp>i</scp>) complexes applicable for asymmetric halogenation?
作者:Daniel von der Heiden、Flóra Boróka Németh、Måns Andreasson、Daniel Sethio、Imre Pápai、Mate Erdelyi
DOI:10.1039/d1ob01532j
日期:——
chiral trans-chelating bis(pyridine)iodine(I) complexes in the development of substrate independent, catalytic enantioselective halofunctionalization has been explored herein. Six novel chiral bidentate pyridine donor ligands have been designed, routes for their synthesis developed and their [N–I–N]+-type halogen bond complexes studied by 15N NMR and DFT. The chiral complexes encompassing a halogen
对映体纯卤化分子作为合成中间体在药物、香料、香精、天然产物、杀虫剂和功能材料的构造中具有极其重要的作用。对映选择性卤代官能化仍然知之甚少,缺乏普遍适用的程序。本文探讨了手性反式螯合双(吡啶)碘( I )配合物在开发与底物无关的催化对映选择性卤代官能化中的适用性。设计了六种新型手性双齿吡啶供体配体,开发了它们的合成路线,并由15研究了它们的 [N-I-N] +型卤素键配合物N核磁共振和密度泛函。包含卤素键稳定的碘鎓离子的手性配合物显示能够有效地将碘鎓转移到烯烃;然而,没有对映选择性。立体选择性的缺乏被证明源于具有可比能量的多个配体构象的可用性和手性配体的空间影响不足。手性催化剂对底物的预组织似乎是对映选择性卤代官能化的必要条件。
Asymmetric Reduction of Cyclic Enones to Allylic Alcohols
作者:Jérôme Hannedouche、Jennifer A. Kenny、Tim Walsgrove、Martin Wills
DOI:10.1055/s-2002-19747
日期:——
Asymmetric transfer hydrogenation of cyclic enones results in highly enantioselective reduction to cyclic allylic alcohols.
环状烯酮的不对称转移加氢反应可高度对映选择性地还原成环状烯丙基醇。
Highly Enantioselective and Regioselective Carbonyl Reduction of Cyclic α,β-Unsaturated Ketones Using TarB-NO<sub>2</sub> and Sodium Borohydride
作者:Jinsoo Kim、John Bruning、Kevin E. Park、David J. Lee、Bakthan Singaram
DOI:10.1021/ol901677b
日期:2009.10.1
Asymmetric 1,2-reduction of alpha,beta-unsaturated ketones using TarB-NO2 and NaBH4 is reported. Simple cycloalkenones give products in low enantiomeric excess. However, cycloalkenones with alpha-substituents, such as halides, alkyl, and aryl, have been enantioselectively reduced with this system to yield chiral allylic alcohols in enantiomeric excess up to 99%. The starting materials for TarB-NO2 are inexpensive, and the boronic acid can be easily recovered in high yield by a simple acid extraction.