title: Catalytic asymmetric enyne addition to aldehdyes and Rh(I)-catalyzed stereoselective domino Pauson-Khand/[4 + 2] cycloaddition.
abstract: The 1,1'-bi-2-naphthol-ZnEt2-Ti(O(i)Pr)4-Cy2NH system is found to catalyze the 1,3-enyne addition to aliphatic aldehydes as well as other aldehydes at room temperature with 75-96% yield and 82-97% ee. This system is also broadly applicable for the highly enantioselective reaction of other alkyl-, aryl-, and silylalkynes with structurally diverse aldehydes. The propargylic alcohols prepared from the catalytic asymmetric enyne addition to aliphatic aldehydes are used to prepare a series of optically active trienynes. In the presence of a catalytic amount of [RhCl(CO)2]2 and 1 atm of CO, the optically active trienynes undergo highly stereoselective domino Pauson-Khand/[4 + 2] cycloaddition to generate optically active multicyclic products. The Rh(I) catalyst is also found to catalyze the coupling of a diyne with CO followed by [4 + 2] cycloaddition to generate an optically active multicyclic product. These transformations are potentially useful for the asymmetric synthesis of polyquinanes containing a quaternary chiral carbon center.
authors: Department of Chemistry, Sichuan University, Chengdu 610064, China.
authors: Wei
authors: W
authors: Chen
authors: Jia-Hui
authors: JH
authors: Tay
authors: Jun
authors: J
authors: Ying
authors: Xiao-Qi
authors: XQ
authors: Yu
authors: Lin
authors: L
authors: Pu
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D061565:Cycloaddition Reaction; D053280:Diynes / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D020005:Propanols / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D000480:Alkynes; D053280:Diynes; D009942:Organometallic Compounds; D020005:Propanols; D012238:Rhodium; C028255:propargyl alcohol