描述了一种温和且操作简单的铜催化乙烯基有氧氧化 β,γ-和 α,β-不饱和酯。该方法具有收率好、底物范围广、化学选择性和区域选择性好、官能团耐受性好等特点。该方法还能够氧化β,γ-和α,β-不饱和醛、酮、酰胺、腈和砜。此外,本催化体系适用于双乙烯基和三乙烯基氧化。发现四甲基胍 (TMG) 作为碱的作用至关重要,但我们也推测它可以作为三氟甲磺酸铜 (II) 的配体来生产活性铜 (II) 催化剂。进行的机械实验表明,通过烯丙基铜 (II) 物质存在一个合理的反应途径。最后,
Sulfur-controlled and rhodium-catalyzed formal (3 + 3) transannulation of thioacyl carbenes with alk-2-enals and mechanistic insights
作者:Qiuyue Wu、Ziyang Dong、Jiaxi Xu、Zhanhui Yang
DOI:10.1039/d1ob00116g
日期:——
A rhodium-catalyzed denitrogenative formal (3 + 3) transannulation of 1,2,3-thiadiazoles with alk-2-enals is achieved and a mechanistic investigation is performed, with an inverse KIE of 0.49 obtained.
Synthesis of 3,6-dihydro-2H-pyran-2-ones via cationic palladium(II) complex-catalyzed tandem [2+2] cycloaddition-allylic rearrangement of ketene with α,β-unsaturated aldehydes and ketones
Treatment of ketene with α,β-unsaturated aldehydes and ketones in the presence of [Pd(dppb)(PhCN)2](BF4)2 leads to the formation of 4-vinyloxetan-2-ones, which rearrange under the conditions to give 3,6-dihydro-2H-pyran-2-ones in a variety of yields, depending on the substituents. Asymmetric induction with up to 57% de has been achieved by using α,β-unsaturated aldehydes bearing an asymmetric carbon
Stereoselective Organocatalytic Synthesis of α,α-Difluoro-γ,γ-Disubstituted Butenals
作者:Satoru Arimitsu、Makoto Nakasone
DOI:10.1021/acs.joc.6b01334
日期:2016.8.5
A highly stereoselective reaction of α,α-difluoro-γ,γ-disubstituted butenals 2 bearing two different substituents at the γ position has been developed with an organocatalytic system of l-proline (30 mol %) and salicylic acid (60 mol %). This novel reaction demonstrated a wide substrate scope and excellent E stereoselectivity in most cases. The obtained difluorinated aldehyde 2a was applied as a useful
Site‐Selective C−H Allylation of Alkanes: Facile Access to Allylic Quaternary sp
<sup>3</sup>
‐Carbon Centers
作者:Yong Yang、Shaopeng Liu、Shuang Li、Zhaohong Liu、Peiqiu Liao、Paramasivam Sivaguru、Ying Lu、Jiaojiao Gao、Xihe Bi
DOI:10.1002/anie.202214519
日期:2023.1.23
The first site-selective C(sp3)−H insertion of unactivated alkanes with non-acceptor vinylcarbenes was achieved by silver catalysis and with bench-stable vinyl-N-triftosylhydrazones as substrates. The corresponding products feature allylicquaternary sp3-carbon centers and were obtained in high yields.
Diastereoselective synthesis of γ,γ-disubstituted β-hydroxy α,α-difluoro-γ-butyrolactones
作者:Tatsuro Ishikawa、Satoru Arimitsu
DOI:10.1016/j.jfluchem.2022.110028
日期:2022.9
The L-proline catalyzed synthesis of α,α-difluoro homoallylic aldehydes was modified, and these aldehydes bearing either aromatic or aliphatic groups the γ-position were obtained with excellent E/Z selectivity (E/Z ≥ 20/1) in a practical manner. Thereafter, the obtained aldehydes were readily transformed into α,α-difluoro homoallylic esters in moderate yields (53–74%) over three steps, maintaining