We have developed catalytic isomerizations of 5-alkynals to γ-alkynyl ketones and cyclopent-1-enylketones using [RhP(OPh)3}2]BF4 as a catalyst. Cu(OTf)2 and AgBF4 are also effective catalysts for the formation of γ-alkynyl ketones. The substituents at the 4-positions in 5-alkynals play important roles in the selection of two different isomerization pathways. The first catalytic endo/trans hydroacylation
Dual Photoredox/Cobalt-Catalyzed Reductive Cyclization of Alkynals
作者:Kento Nakamura、Hina Nishigaki、Yoshihiro Sato
DOI:10.1021/acscatal.3c06206
日期:2024.3.1
alkynals using H2O for the catalyst turnover. This method was applied to aliphatic and aromatic aldehydes for five-, six-, and seven-membered (heterocyclic) ring formation with various substitutions on alkyne units. This H2O-added protocol was further developed into a one-pot transformation fromacetals through in situ generated aldehydes, which shortened the synthetic path of the reaction.
取代环醇是药学上必需的支架之一。在这里,我们报道了使用 H 2 O进行催化剂周转的光氧化还原/钴催化的炔醛还原环化。该方法适用于脂肪族和芳香族醛,形成五元、六元和七元(杂环)环,并在炔单元上进行各种取代。这种添加H 2 O的方案进一步发展为从缩醛到原位生成醛的一锅转化,从而缩短了反应的合成路径。
Rhodium-Catalyzed Intramolecular Hydroacylation of 5- and 6-Alkynals: Convenient Synthesis of ?-Alkylidenecycloalkanones and Cycloalkenones
novel intramolecularhydroacylation of 5- and 6-alkynals leading to alpha-alkylidenecycloalkanones was accomplished by using cationic a rhodium(I)/BINAP complex. For all cyclizations described, a single (E)-olefin isomer was obtained. At elevated temperature, hydroacylation and double bond migration of 5- and 6-alkynals proceeded in a one-pot reaction to give cycloalkenones. An intramolecular hydroacylation