Synthesis and stereostructure–activity relationship of a synthetic pyrethroid, 2-chloro-1-methyl-3-phenylcyclopropylmethyl-3-phenoxybenzyl ether
摘要:
Of the four diastereoisomers of 2-chloro-1-methyl-3-phenylcyclopropylmet 3-phenoxybenzyl ether 5, a new type of synthetic pyrethroid, which have been synthesized, only the (1R*,2S*,3S*)-isomer 5a showed significant insecticidal activity against the tobacco cutworm and the common mosquito. Two enantiomers (1R,2S,3S)-(-)-5a and (1S,2R,3R)-(+)-5a were prepared by the optical resolution process, and their absolute configurations were determined by chemical derivatization via predictable asymmetric cyclopropanation. Bioassay showed that the (1R,2S,3S)-(-)-5a was active, while (1S,2R,3R)-(+)-5a was not. The geometry around the asymmetric centre of the (1R,2S,3S)-enantiomer was correlated with that of representative pyrethroids which are both optically active and have insecticidal activity.
Stability, Reactivity, Solution, and Solid-State Structure of Halomethylzinc Alkoxides
作者:André B. Charette、Carmela Molinaro、Christian Brochu
DOI:10.1021/ja010837+
日期:2001.12.1
regarding the development of a Lewis acid-catalyzed cyclopropanation of allylic alcohols with bis(iodomethyl)zinc. Iodomethylzinc alkoxides can be formed by treatment of an alcohol with bis(iodomethyl)zinc. These species are not prone to undergo cyclopropanation at low temperature but the addition of a Lewisacid in catalytic amounts induces the cyclopropanationreaction. Using this procedure, we demonstrated
Enantioselective Cyclopropanation of Allylic Alcohols with Dioxaborolane Ligands: Scope and Synthetic Applications
作者:André B. Charette、Hélène Juteau、Hélène Lebel、Carmela Molinaro
DOI:10.1021/ja982055v
日期:1998.11.1
the conversion of allylicalcohols into the corresponding enantiomerically enriched cyclopropanes using bis(iodomethyl)zinc. A variety of chiral, nonracemic cyclopropylmethanols could be obtained according to this method. This methodology was extended with success to the cyclopropanation of unconjugated and conjugated polyenes and homoallylic alcohols. The cyclopropanation of allylic carbamates has also
Two rhodium(II) ions work together: [Rh2(S‐tbpttl)4] is an exceptionally effective catalyst for enantioselectivecyclopropenationreactions of 1‐alkynes with α‐alkyl‐α‐diazoacetates (see scheme). Cyclopropenation is preferred over alkene formation through a 1,2‐hydride shift.
Enantio- and diastereoselective cyclopropanation with tert-butyl α-diazopropionate catalyzed by dirhodium(II) tetrakis[N-tetrabromophthaloyl-(S)-tert-leucinate]
The first successful example of a catalytic asymmetriccyclopropanation with α-diazopropionates is described. The cyclopropanation reaction of 1-aryl-substituted and related conjugated alkenes with tert-butyl α-diazopropionate has been achieved by catalysis with dirhodium(II) tetrakis[N-tetrabromophthaloyl-(S)-tert-leucinate], Rh2(S-TBPTTL)4, providing the corresponding cyclopropane products containing
The use of 1,2-O-isopropylidene-α-d-xylofuranose as a chiral auxiliary in asymmetric cyclopropanation reactions
作者:José M. Vega-Pérez、Ignacio Periñán、Fernando Iglesias-Guerra
DOI:10.1016/j.tetasy.2009.02.062
日期:2009.5
1,2-O-isopropylidene-d-xylofuranose, as a chiralauxiliary, is described. The Simmons–Smith cyclopropanationreaction of the corresponding alkenylidene derivatives with CH2I2/ZnEt2, in different reaction conditions, took place with high stereoselectivity. The diastereomeric excess in each case depended on the solvent and the temperature used in the reaction. The absolute configuration of the new stereogenic
描述了衍生自作为手性助剂的1,2 - O-异亚丙基-d-木呋喃糖的环丙基亚甲基缩醛的立体选择性合成。在不同的反应条件下,相应的链烯基衍生物与CH 2 I 2 / ZnEt 2的Simmons-Smith环丙烷化反应具有很高的立体选择性。在每种情况下,非对映异构体过量取决于反应中所用的溶剂和温度。通过手性助剂的环丙烷部分的酸水解确定了形成的新的立体异构中心的绝对构型,该手性助剂也被回收了。