A Copper-Catalyzed Method for the Facially Selective Addition of Grignard Reagents to Cyclopropenes
作者:Lian-an Liao、Joseph M. Fox
DOI:10.1021/ja0278234
日期:2002.12.1
A Cu-catalyzed method for the addition of Grignardreagents to 1-alkyl-3-hydroxymethylcyclopropenes and their MOM ethers is described. The face of addition is syn relative to the hydroxymethyl and alkoxymethyl groups. Excellent diastereoselectivity is observed for a range of alkyl, alkenyl, and alkynylmagnesium halides. The addition reactions create chiral all-carbon quaternary centers, and the cyclopropylmetals
描述了将格氏试剂添加到 1-烷基-3-羟甲基环丙烯及其 MOM 醚的 Cu 催化方法。相对于羟甲基和烷氧基甲基而言,加成是顺式的。对于一系列烷基、烯基和炔基卤化镁,观察到了出色的非对映选择性。加成反应产生手性全碳四元中心,产生的环丙基金属可以与亲电试剂反应产生高度官能化的环丙烷。
Carbonylative C−C Bond Activation of Electron-Poor Cyclopropanes: Rhodium-Catalyzed (3+1+2) Cycloadditions of Cyclopropylamides
作者:Andrew G. Dalling、Takayuki Yamauchi、Niall G. McCreanor、Lydia Cox、John F. Bower
DOI:10.1002/anie.201811460
日期:2019.1.2
Rh‐catalyzed carbonylative C−C bond activation of cyclopropylamides generates configurationally stable rhodacyclopentanones that engage tethered alkenes in (3+1+2) cycloadditions. These studies provide the first examples of multicomponent cycloadditions that proceed through C−C bond activation of “simple” electron poor cyclopropanes.
Versatility in the Brook Rearrangement for the Selective Ring‐Opening of Three‐Membered Rings
作者:Coralie Tugny、Fa‐Guang Zhang、Ilan Marek
DOI:10.1002/chem.201805006
日期:2019.1.2
From a single α‐silylated carbinol intermediate, easily accessible by carbometallation of cyclopropenes, various scaffolds featuring a quaternary carbon stereocenter could be obtained selectively. The selectivity towards these different products was achieved by either changing the experimental conditions or the nature of the organometallic species involved.
Functionalized Cyclopropenes and Methylenecyclopropenes from Dianions of 3-Hydroxymethylcyclopropenes
作者:Joseph Fox、Matthew Hassink
DOI:10.1055/s-0031-1290822
日期:——
Abstract 1,2-Disubstituted 3-hydroxymethylcyclopropene derivatives have been synthesized by reacting the dianions of 1-alkyl-3-hydroxymethylcyclopropenes with a range of electrophiles. Additionally, a complementary procedure is described for one-pot sequential alkylation/rearrangement to provide a convenient synthesis of a chiral methylenecyclopropane directly from a 1-alkyl-3-hydroxymethylcyclopropene
direct addition reaction of chloroform to cyclopropenes under triethylborane-mediated radicalreaction conditions to provide trichloromethylcyclopropanes has been developed. In contrast, using dimethylzinc as a radical initiator led to the formation of unconjugated esters via a domino sequence involving the addition of the trichloromethylradical, rearrangement and ring-opening reactions.