Isomerization of Allyl Ethers Initiated by Lithium Diisopropylamide
摘要:
Lithium diisopropylamide (LDA) promotes virtually quantitative conversion of allylic ethers to (Z)-propenyl ethers. It was discovered that allylic ethers can be isomerized efficiently with very high stereoselectivity to (Z)-propenyl ethers by LDA in THF at room temperature. The reaction time for the conversion increases with more sterically hindered allylic ethers. Different amides were also compared with LDA for their ability to effect this isomerization.
Lewis Acid-Catalyzed Halonium Generation for Morpholine Synthesis and Claisen Rearrangement
作者:Jeewani P. Ariyarathna、Nur-E Alom、Leo P. Roberts、Navdeep Kaur、Fan Wu、Wei Li
DOI:10.1021/acs.joc.1c02804
日期:2022.3.4
We disclose here practical strategies toward the synthesis of morpholines and Claisenrearrangement products based on the divergent reactivity of a common halonium intermediate. These reactions employ widely available alkenes in a Lewis acid-catalyzed halo-etherification process that can then transform them into the desired products with exceptional regioselectivity for both activated and unactivated
carboxylation of unactivated alkenes with CO2•− has never been reported. Here we report visible-light photocatalytic di- and hydro-carboxylation of unactivated alkenes with CO2. In contrast to previous reports limited to activated alkenes, diverse unactivated aliphatic alkenes undergo selective carboxylations to give carboxylic acids, dicarboxylic acids and unnatural α-amino acid derivatives in moderate to good
Isomerization of Allyl Ethers Initiated by Lithium Diisopropylamide
作者:Chicheung Su、Paul G. Williard
DOI:10.1021/ol102029u
日期:2010.12.3
Lithium diisopropylamide (LDA) promotes virtually quantitative conversion of allylic ethers to (Z)-propenyl ethers. It was discovered that allylic ethers can be isomerized efficiently with very high stereoselectivity to (Z)-propenyl ethers by LDA in THF at room temperature. The reaction time for the conversion increases with more sterically hindered allylic ethers. Different amides were also compared with LDA for their ability to effect this isomerization.
Borowiecki, Lucjan; Welniak, Miroslaw, Polish Journal of Chemistry, 1989, vol. 63, # 1-3, p. 149 - 156