Synthesis of conjugated γ- and δ-lactones from aldehydes and ketones via a vinylation(allylation)-ring closing metathesis–oxidation sequence
作者:J.Alberto Marco、Miguel Carda、Santiago Rodrı́guez、Encarnación Castillo、Marı́a N. Kneeteman
DOI:10.1016/s0040-4020(03)00584-2
日期:2003.6
aldehydes and ketones followed by O-allylation of the obtained carbinols gave the corresponding allyl or homoallyl ethers, respectively. Ring-closing metathesis of these compounds afforded in many cases cyclic ethers (dihydrofurans and dihydropyrans, respectively) bearing disubstituted and trisubstituted CC bonds. These were then subjected to allylic oxidation to yield conjugated γ- and δ-lactones. Reasons
Synthesis of Conjugated γ- and δ-Lactones from Aldehydes and Ketones via a Vinylation/Allylation-Ring Closing Metathesis-Oxidation Sequence
作者:Miguel Carda、Encarnación Castillo、Santiago Rodríguez、Santiago Uriel、J. Alberto Marco
DOI:10.1055/s-1999-2897
日期:——
Nucleophilic C-vinylation or C-allylation of aldehydes and ketones followed by O-allylation of the obtained carbinols gave the corresponding allyl ethers. Ring-closing metathesis of the latter afforded cyclic ethers (dihydrofurans and dihydropyrans, respectively) which were then subjected to allylic oxidation to yield conjugated γ- and δ-lactones.
conversion of allyl homoallyl ethers to gamma,delta-unsaturated carbonylcompounds. For example, treatment of 1-allyl-1-allyloxycyclohexane in the presence of catalytic amounts of [Ir(cod)Cl](2), PCy(3), and Cs(2)CO(3) in toluene at 100 degrees C afforded 4-cyclohexyliden-2, 3-dimethylbutanal in 74% yield. The reaction presumably proceeds through double bond migration to allyl vinyl ethers, which then
Homologation of Monoterpenoids into New Sesquiterpenoidsvia Tandem Isomerisation/Claisen Rearrangement Reactions with Three-Component Ruthenium Catalysts, and Ru(methallyl)2(COD) Revealed by High Throughput Screening Techniques
作者:Jérôme Le Nôtre、Rachid Touzani、Olivier Lavastre、Christian Bruneau、Pierre H. Dixneuf
DOI:10.1002/adsc.200404391
日期:2005.5
system B based on a ruthenium source Ru3(CO)12, a bulky imidazolinium salt and Cs2CO3 appears very efficient for the transformation of a 1,7-diene into a γ,δ-unsaturated aldehyde via tandemisomerisation/Claisenreactions. 1,6-Dienes arising from the terpenoids menthone and myrtenal were selectively transformed into the corresponding unsaturated aldehydes with catalyst B. Highthroughput experiments were
基于钌源Ru 3(CO)12,庞大的咪唑啉鎓盐和Cs 2 CO 3的催化体系B对于将1,7-二烯通过串联异构化转化为γ,δ-不饱和醛非常有效/克莱森的反应。由萜烯类薄荷酮和Myrtenal产生的1,6-二烯用催化剂B选择性地转化为相应的不饱和醛。进行高通量实验以评估其他多组分催化剂:这些串联反应的金属源/配体/碱。发现意外的催化剂是Ru(甲基烯丙基)2(COD),无需其他配体或试剂即可操作。
Base-induced rearrangement of dihydropyran oxides: A novel synthesis of cyclic enol ethers with a hydroxy-function in the allylic position
作者:Bernd Schmidt
DOI:10.1016/s0040-4039(99)00776-5
日期:1999.6
closing metathesis of allyl-homoallyl ethers, epoxidation of the resulting dihydropyrans, and rearrangement of the dihydropyran oxides with LDA provides convenient access to 2,3-dihydropyrans with a hydroxy group in the 4-position. The products may serve as starting materials for e.g. the Carbon-Ferrier rearrangement.