Nucleophilic Phosphine-Catalyzed Iodocyclization of Isoprenoids Bearing an Oxygen Terminal Group
摘要:
The nucleophilic phosphine-catalyzed diastereoselective iodocyclization of linear isoprenoids bearing an oxygen terminal group was investigated. TBDMS ether of homogeraniol and TBDMS ester of homogeranic acid were successfully converted to the corresponding iodopolycyclic products in the presence of a catalytic amount of triphenylphosphine with complete diastereoselectivity.
Aerobic Catalytic Features in Photoredox- and Copper-Catalyzed Iodolactonization Reactions
作者:Jeewani Poornima Ariyarathna、Fan Wu、Sara Katelyn Colombo、Charleese Marisa Hillary、Wei Li
DOI:10.1021/acs.orglett.8b02771
日期:2018.10.19
evaluations and comparison of two important aerobic catalytic oxidation processes, aerobic copper catalysis and photoredox catalysis, are performed. Interesting and distinct catalytic behaviors were observed for a common reaction of iodolactonization of alkenoic acids. Namely, the aerobic copper catalysis requires the formation of a copper carboxylate, whereas the aerobic photoredox catalysis requires the addition
Achiral Counterion Control of Enantioselectivity in a Brønsted Acid-Catalyzed Iodolactonization
作者:Mark C. Dobish、Jeffrey N. Johnston
DOI:10.1021/ja301858r
日期:2012.4.11
Highly enantioselective halolactonizations have been developed that employ a chiral proton catalyst-N-iodosuccinimide (NIS) reagent system in which the Brønsted acid is used at catalyst loadings as low as 1 mol %. An approach that modulates the achiral counterion (equimolar to the neutral chiral ligand-proton complex present at low catalyst loadings) to optimize the enantioselection is documented for
4-(Dimethylamino)pyridine-catalysed iodolactonisation of γ,δ-unsaturated carboxylic acids
作者:Chuisong Meng、Zhihui Liu、Yuxiu Liu、Qingmin Wang
DOI:10.1039/c5ob00806a
日期:——
4-(Dimethylamino)pyridine functioned as an excellent catalyst for iodolactonization reactions of γ,δ-unsaturated carboxylic acids, affording γ-lactones, δ-lactones, or both.
among stereocontrolled iodocyclizations mostly substrate-controlled versions using a chiral auxiliary have been successfully investigated. This work reports on stereoselective reagent-controlled iodolactonizations applying a new method using a combination of ICl and a primary amine leading to the highest selectivities known so far.
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。