A highly efficient asymmetric Mannich-type reaction between α-tetralone-derived β-keto esters/amides and 1,3,5-triaryl-1,3,5-triazinanes was realized in the presence of chiral N,N′-dioxide–Ni(II) or Mg(II) complex. A variety of optically active β-amino compounds with all-carbon quaternary stereocenters were obtained in good yields with excellent enantioselectivities. A possible transition state was
Cooperative Palladium/Brønsted Acid Catalysis toward the Highly Enantioselective Allenylation of β-Keto Esters
作者:Henning J. Loui、Christoph Schneider
DOI:10.1021/acs.orglett.2c00179
日期:2022.2.25
We report the first enantioselective allenylation of Pd enolates enabled by cooperative Pd/Brønsted acid catalysis employing β-keto esters and propargyl alcohols. The enantioselectivity originates solely from an in-situ-generated chiral metal enolate in an open transition state with no additional binding of the propargyl component to the catalyst. Thus a broad substrate scope was established, furnishing
Construction of Vicinal Quaternary Carbon Centers via Cobalt-Catalyzed Asymmetric Reverse Prenylation
作者:Minghe Sun、Jia-Feng Chen、Shufeng Chen、Changkun Li
DOI:10.1021/acs.orglett.8b04030
日期:2019.3.1
A highly enantioselective cobalt-catalyzed reverse prenylation of β-ketoester with tertiary allylic carbonate to construct vicinal all-carbon quaternarycarboncenters has been developed. By using the cobalt/(S,S)Ph-BPE complex generated in situ with zinc reduction, excellent branched to linear selectivity (>20:1) and up to 92% ee have been obtained.