Application of the diastereoselective photodeconjugation of α,β-unsaturated esters to the synthesis of gymnastatin H
作者:Ludovic Raffier、Olivier Piva
DOI:10.3762/bjoc.7.21
日期:——
The asymmetric synthesis of gymnastatin H has been achieved by using the photoisomerisation of a conjugated ester to its beta,gamma-unsaturated isomer through the protonation of a in situ generated dienol as key step. Thanks to diacetone D-glucose used as a chiral alkoxy group, the protonation occurred well onto one of the two diastereotopic faces with very high yields and selectivities. Moreover,
Gynastatin H 的不对称合成是通过使用共轭酯的光异构化为其 β,γ-不饱和异构体通过原位生成的二烯醇的质子化作为关键步骤来实现的。由于双丙酮D-葡萄糖用作手性烷氧基,质子化以非常高的产率和选择性很好地发生在两个非对映体之一上。此外,通过这种方式控制了目标分子的 C-6 中心的构型。
Copper-Photocatalyzed <i>Contra</i>-Thermodynamic Isomerization of Polarized Alkenes
The contra-thermodynamic isomerization of α- and β-substituted cinnamate derivatives catalyzed by the Cu(OAc)2/rac-BINAP complex under blue light irradiation is reported. The use of an oxazolidinone template, which favored the complexation of the copper catalyst to the substrate, allowed the E → Z isomerization of the catalytically formed chromophore under simple and robust reaction conditions in good
An Efficient and Practical Method for Olefin Dihydroxylation
作者:Zhi-bin Luo、Jimin Xie、Hong-fei Lu、Chen Zhao
DOI:10.1055/s-0035-1562783
日期:——
the dihydroxylation of various olefin derivatives with commercial KMnO4 as the oxidant in the presence of a quaternary ammonium salt. This practical procedure is suitable for large-scale production of cis-dihydroxy compounds, even those bearing primary and secondary alcohol groups, without overoxidation. An efficient and economic procedure was developed for the dihydroxylation of various olefin derivatives
1-Acetoxy and 1-Silyloxy-1,3-dienes via Reductive Homologation of α, β,-Unsaturated Esters
作者:Conrad J Kowalski、G.Sankar Lal
DOI:10.1016/s0040-4039(00)95441-8
日期:1987.1
α, β-Unsaturated esters (1) are stereospecifically converted in a one-pot preparation into 1-oxygenated-,-dienes (4). This reductivehomologation proceeds via lithiumhydridereduction of the ene ynolateanion (2) to the dienolate anion 3, affording 1-acetoxy- or 1-silyloxy-1,3-dienes in yields of about 45–55%.
Novel dioctatin derivatives and production process thereof
申请人:Muraoka Yasuhiko
公开号:US20080312080A1
公开(公告)日:2008-12-18
To provide dioctatin derivatives, a production process thereof, an aflatoxin production inhibitor containing the dioctatin derivative, and a method of controlling aflatoxin contamination by use of the aflatoxin production inhibitor containing the dioctatin derivative. The present invention provides dioctatin derivatives represented by the following Structural Formula (I):
where R
1
and R
2
each represent CH
3
—(CH
2
)
n
—, (CH
3
)
2
CH—CH
2
— or C
6
H
5
—CH
2
—; n represents an integer of 2 to 6; X
1
and X
2
each represent CH
3
or hydrogen atom; and Y represents 2-amino-2-butenoic acid or amino acid residue, with compounds where R
1
and R
2
are each CH
3
(CH
2
)
4
—, X
2
is a hydrogen atom and Y is 2-amino-2-butenoic acid being excluded.