the visible light induced simple copper(II) chloride catalyzedoxidation of diarylacetylenes to α-diketones by molecular oxygen at roomtemperature. The in situ generated copper(II)-superoxo complex is a light-absorbing species that oxidizes inert diarylacetylenes to α-diketones. In contrast to reported photochemical processes, the current oxidation protocol does not require any exogenous photocatalyst
HETEROAROMATIC COMPOUNDS HAVING SPHINGOSINE-1-PHOSPHATE (S1P) RECEPTOR AGONIST BIOLOGICAL ACTIVITY
申请人:Beard Richard L.
公开号:US20080064872A1
公开(公告)日:2008-03-13
A novel compound having agonist activity at the S
1
P
3
receptor which is represented by the formula I
wherein
X is selected from the group consisting of CR
3
, N and NO;
Y is selected from the group consisting of CR
3
, N and NO;
Z is selected from the group consisting of CR
3
, N and NO;
and at least one of X, Y and Z is N or NO;
V is O or NOR
4
R
1
is an aryl group;
R
2
is an aryl group;
R
3
is selected from the group consisting of H and alkyl; and 2 of
said R
3
groups may together form a cyclic alkyl ring having from 3 to 6 carbon atoms;
R
4
is selected from the group consisting of H and alkyl;
a is 0 or an integer of from 1 to 6;
b is 0 or 1;
c is 0 or 1;
f is 0 or an integer of 1 or 2;
x is 0 or 1;
y is 0 or an integer of from 1 to 3; and
z is 0 or an integer of from 1 to 3.
A catalyst-free and transition-metal-free method for the synthesis of 1,2-diketones from aerobic alkyne oxidation was reported. The oxidation of various internal alkynes, especially more challenging aryl-alkyl acetylenes, proceeded smoothly with inexpensive, easily handled, and commercially available potassium persulfate and an ambient air balloon, achieving the corresponding 1,2-diketones with up
Photoredox Catalytic Phosphite‐Mediated Deoxygenation of α‐Diketones Enables Wolff Rearrangement and Staudinger Synthesis of β‐Lactams
作者:Hui Yang、Haijun Li、Guo Wei、Zhiyong Jiang
DOI:10.1002/anie.202107080
日期:2021.9
activation of C=O bonds by exploiting the photoredox chemistry of 1,3,2-dioxaphospholes, readily accessible fromα-diketones and trialkyl phosphites, is reported. This mild and environmentally friendly strategy provides an unprecedented and efficient access to the Wolff rearrangement reaction which traditionally entails α-diazoketones as precursors. The resulting ketenes could be precisely trapped by