Allylindation of Cyclopropenes in Organic and Aqueous Media: Switching the Regio- and Stereoselectivity Based on the Chelation with a Hydroxyl Group and the Crystal Structure of the Cyclopropylindium Product
摘要:
Hydroxy-bearing cyclopropenes react with allylindium reagents to undergo clean allylindation both in organic and aqueous media, in which the chelation of the hydroxyl group to indium plays the central role. The regio-and stereoselectivity have been regulated both by the location of the hydroxyl group in the molecules and the reaction solvents. In particular, the allylindation in water shows marked differences from that in organic solvents; the regio- and stereoselectivity have totally been reversed compared with those in organic solvents. Unusually stable cyclopropylindium compounds have been isolated from the reaction of 1-(omega -hydroxyalkyl)-cyclopropenes and the structure has fully been established by X-ray crystallography.
Visible-Light-Mediated Addition of Phenacyl Bromides onto Cyclopropenes
作者:Nitin S. Dange、Ashique Hussain Jatoi、Frédéric Robert、Yannick Landais
DOI:10.1021/acs.orglett.7b01651
日期:2017.7.7
Visible-light-promoted addition of α-bromoacetophenones onto the cyclopropene π-system in the presence of the fac-Ir(ppy)3 catalyst was shown to afford the corresponding 1(4H)-naphthalenones. The syn-carboarylation of the cyclopropene is followed by a cyclopropane ring opening under the basic conditions, allowing the formation of two C–C bonds and the generation of 1(4H)-naphthalenones bearing an all-carbon
Free-Radical Carbocyanation of Cyclopropenes: Stereocontrolled Access to All-Carbon Quaternary Stereocenters in Acyclic Systems
作者:Nitin S. Dange、Frédéric Robert、Yannick Landais
DOI:10.1021/acs.orglett.6b03163
日期:2016.12.2
Free-radical carbocyanation of cyclopropenes offers straightforward access to tetrasubstituted cyclopropanes in satisfying yields with moderate diastereoselectivity. The incorporation of various functional groups on the cyclopropane ring allows a subsequent base-mediated ring-opening reaction leading to functionalized acyclic systems having an all-carbon quaternary stereocenter.