Rhodium-Catalyzed Chemo-, Regio-, and Enantioselective [2 + 2 + 2] Cycloaddition of Alkynes with Isocyanates
作者:Ken Tanaka、Azusa Wada、Keiichi Noguchi
DOI:10.1021/ol052041b
日期:2005.10.1
chemoselective [2 + 2 + 2] cycloaddition of alkynes with isocyanates leading to a wide range of 2-pyridones. This method was successfully applied to the chemo-, regio-, and enantioselective synthesis of axially chiral 2-pyridones from unsymmetrical alpha,omega-diynes, bearing an ortho-substituted phenyl at one terminal position, and alkyl isocyanates.
Iridium-Catalyzed [2+2+2] Cycloaddition of α,ω-Diynes with Isocyanates
作者:Gen Onodera、Mari Suto、Ryo Takeuchi
DOI:10.1021/jo202083z
日期:2012.1.20
This regioselectivity could be explained by the reaction of iridacyclopentadiene with a nitrogen–carbon double bond. The regioselectivity of the reaction of malonate-derived diyne was controlled by a steric effect, while that of the reaction of ester-tethered diyne was controlled by an electronic effect. [Ir(cod)Cl]2/chiral diphosphine catalyst could be used for the enantioselective synthesis of C–N