300372-44-5Relevant academic research and scientific papers
Palladium(II)-catalyzed asymmetric cyclization of (Z)-4′-acetoxy-2′-butenyl 2-alkynoates. Role of nitrogen-containing ligands in palladium(II)-mediated reactions
Zhang,Lu,Han
, p. 7676 - 7684 (2001)
Pd(OAc)2 combined with nitrogen-containing ligands (e.g., 2,2′-bipyridine) catalyzed the cyclization of (Z)-4′-acetoxy-2′-butenyl 2-alkynoates (1) in acetic acid to afford the α-(Z)-acetoxyalkylidene-β-vinyl-γ-butyrolactones (2) with high efficiency and high stereoselectivity. The nitrogen-containing ligands, like halides, served to favor β-heteroatom elimination over β-hydride elimination in Pd(II)-mediated reactions. The generality of this ligand effect was probed in both stoichiometric and catalytic reactions. With these results in hand, the catalytic asymmetric protocol was achieved with high enantioselectivity (up to 92% ee) when pymox (pyridyl monooxazoline) or bisoxazoline was used. The absolute configuration of the products and the synthetic utility of this asymmetric transformation were established through the convenient synthesis of (3S)-(+)-A-factor.
The use of iminopyridines as efficient ligands in the palladium(II)-catalyzed cyclization of (Z)-4′-acetoxy-2′-butenyl 2-alkynoates
Song, Juan,Shen, Qi,Xu, Fan,Lu, Xiyan
, p. 5148 - 5153 (2008/02/01)
Iminopyridines were found to be a sort of efficient bidentate ligands for the palladium(II)-catalyzed cyclization of (Z)-4′-acetoxy-2′-butenyl 2-alkynoates in acetic acid to afford the α-(Z)-acetoxyalkylidene-β-vinyl-γ-butyrolactones. The iminopyridine li
Highly enantioselective syntheses of functionalized α-methylene-γ-butyrolactones via Rh(I)-catalyzed intramolecular Alder ene reaction: Application to formal synthesis of (+)-pilocarpine
Lei, Aiwen,He, Minsheng,Zhang, Xumu
, p. 8198 - 8199 (2007/10/03)
A highly enantioselective Rh(I)-catalyzed intramolecular Alder ene reaction has been developed. The desired products, 3-vinyl, vinyl acetate, and vinyl ether-substitued α-methylene-γ-butyrolactones were formed in high yields. Aldehydes were produced with
