Visible‐Light‐Promoted Oxy‐difluoroalkylation of Aryl Alkynes for the Synthesis of
<i>β</i>
‐Fluoroenones and
<i>α</i>
‐Difluoroalkyl Ketones
作者:Zhong Zhang、Xiangqian Li、Dayong Shi
DOI:10.1002/adsc.202100289
日期:2021.7
synthesis of (E)-β-fluoroenones and α-difluoroalkyl ketones have been achieved. By employing water as oxygen source, potassium carbonate as base, tetrasubstituted β-fluoroenones could be regio- and stereoselectively synthesized by oxy-difluoroalkylation of alkynes under visible light irradiated with moderate to good yields. α-Difluoroalkyl ketones could be obtained while using phenylpyridine as base
一种选择性合成( E ) -β-氟烯酮和α-二氟烷基酮的方法已经实现。以水为氧源,碳酸钾为碱,在可见光照射下,炔烃的氧二氟烷基化反应可以区域选择性和立体选择性地合成四取代的β-氟代烯酮,收率适中。以苯基吡啶为碱可制得α-二氟烷基酮。这种改造具有条件温和、功能耐受性广、步骤经济等特点。大规模转化和进一步衍生化显示了其在有机合成中的潜在应用。
Palladium-Catalyzed Intermolecular Hydroamination of Alkynes: A Dramatic Rate-Enhancement Effect of <i>o</i>-Aminophenol
作者:Tomohiro Shimada、Yoshinori Yamamoto
DOI:10.1021/ja027683y
日期:2002.10.1
The hydroamination of alkynes using o-aminophenol proceeds in very high to good yields in the presence of Pd(NO3)2 catalyst. Remarkable rate enhancement with o-aminophenol is presumably due to the chelation effect of the ortho OH group to palladium.
Novel Synthesis of Disubstituted Alkyne Using Molybdenum Catalyzed Cross-Alkyne Metathesis
作者:Naotake Kaneta、Ken Hikichi、Shin-ichi Asaka、Motokazu Uemura、Miwako Mori
DOI:10.1246/cl.1995.1055
日期:1995.11
A novel disubstitutedalkyne synthesis was developed using molybdenum catalyzed cross-alkyne metathesis by Mortreux’s catalyst [Mo(CO)6-p-ClC6H4OH]. The reaction was carried out using Mo(CO)6 (5 mol% for total amounts of alkynes) and p-ClC6H4OH (1 equiv.) in the presence of an excess amount of another alkyne (3∼11 equiv.) in refluxing toluene.
Reaction of Alkyne Having Hydroxyphenyl Group with Mo(CO)<sub>6</sub>
作者:Naotake Kaneta、Tomoe Hirai、Miwako Mori
DOI:10.1246/cl.1995.627
日期:1995.8
The reaction of m-and p-hydroxyphenylpropyne, 1a and 1b, with Mo(CO)6 (5 mol%) affords metathesis products, 2a and 2b, in 78% and 14% (conversion yield, 78%) yields, respectively. However, o-hydroxyphenylpropyne 1f gave trimerization product 4 in 65% yield.
Chalcones can unusually serve as the precursors of acetophenones which then undergo formal (4+1) cyclization with internal alkynes via rhodium(III) catalysis in a regio- and chemoselective manner. 1-Indanones containing quaternary carbon centers along with reusable aryl aldehydes were formed by this annulation. This discovery enables a practical two-step protocol to indanones from the reaction of acetophenones