Palladium-Catalyzed Asymmetric Construction of Vicinal Tertiary and All-Carbon Quaternary Stereocenters by Allylation of β-Ketocarbonyls with Morita-Baylis-Hillman Adducts
β‐ketocarbonyls with Morita–Baylis–Hillman adducts has been developed using a spiroketal‐based diphosphine (SKP) as the ligand, thus affording a range of densely functionalized products bearing vicinal tertiary and all‐carbon quaternary stereodyad in high selectivities. The utility of the protocol was demonstrated by the facilesynthesis of some complex molecules by simple product transformations.
Acetates of Baylis-Hillman adducts derived from ethyl acrylate, methyl vinyl ketone, and acrylonitrile were coupled with allyltributylstannane using Pd(PPh3)4 or Pd(dba)2 as the catalyst at room temperature to afford the corresponding trisubstituted alka-1,5-dienes in good to high yields.
A palladium‐catalyzed asymmetric allyl–allyl cross‐coupling of acetates of racemic Morita–Baylis–Hillman adducts and allylB(pin) has been developed using a spiroketal‐based bis(phosphine) as the chiral ligand, thus affording a series of chiral 1,5‐dienes bearing a vinylic ester functionality in good yields, high branched regioselectivities, and uniformly excellent enantioselectivities (95–99 % ee)
An enantioselective radical alkylation of 4-alkyl-1,4-dihydropyridines with Morita–Baylis–Hillman (MBH) adducts has been reported. The SN2-type products are predominant. This reaction is enabled by dual photoredox/palladiumcatalysis. The alkylation products are provided in good yields with good regio- and enantioselectivity. The use of Ding’s spiroketal-based bis(phosphine) (SKP) ligand is crucial
已经报道了 4-烷基-1,4-二氢吡啶与 Morita-Baylis-Hillman (MBH) 加合物的对映选择性自由基烷基化。S N 2 型产品占主导地位。该反应是通过双光氧化还原/钯催化实现的。烷基化产物以良好的产率和良好的区域选择性和对映选择性提供。Ding 的基于螺缩酮的双(膦)(SKP)配体的使用对于实现令人满意的区域选择性和对映选择性至关重要。生成的 α,β-不饱和酯可以很容易地还原为合成有用的手性烯丙醇。