Mild and Efficient Synthesis of (Z)-α-Chloroalkylidene-β-lactones via the PdCl2-Catalyzed Cyclocarbonylation of 2-Alkynols
摘要:
A mild and efficient methodology involving PdCl2-catalyzed cyclocarbonylation of 2-alkynols with CuCl2 for the synthesis of (Z)-alpha-chloroalkylidene-beta-lactones was developed. Using the readily available optically active propargylic alcohols allows convenient synthesis of the corresponding (Z)-alpha-chloroalkylidene-beta-lactones with high ee values. cis-Chloropalladation was observed as the major pathway, which is unique as compared to the reported data.
Studies on Pd(II)-Catalyzed Synthesis of (<i>Z</i>)-α-Haloalkylidene-β-lactones from Cyclocarbonylation of 2-Alkynols and the Subsequent Coupling Reactions
作者:Shengming Ma、Bin Wu、Xuefeng Jiang、Shimin Zhao
DOI:10.1021/jo0480038
日期:2005.4.1
A good regio- and stereoselectivity was observed for the PdCl2-catalyzed cyclocarbonylation of 2-alkynols with CuCl2 affording (Z)-alpha-chloroalkylidene-beta-lactons. The highly optically active (Z)-alpha-chloroalkylidene-beta-lactones could be easily prepared from the readily available optically active propargylic alcohols. The Pd(II)-catalyzed cyclocarbonylation of 2-alkynols with CuBr2 was also studied. Although the yields of (Z)-alpha-bromoalkylidene-beta-lactones were low, due to the relatively higher activity of the C-Br bond, the coupling reactions of (Z)-alpha-bromoalkylidene-beta-lactones were quite smooth to afford the corresponding products in high yields. A rationale for this reaction is discussed.
Highly Efficient Suzuki Coupling Reaction of α-Chloroalkylidene-β-lactones and β-Lactams with Organoboronic Acids
-β-lactones and (E)-α-chloroalkylidene-β-lactams via the Suzuki cross-coupling reaction is reported in this paper. Alkyl, heteroaromatic, substituted phenyl- and alkenylboronic acids can be coupled with a wide variety of α-chloroalkylidene-β-lactones and β-lactams in excellent yields within a short period of time. The cross-coupling reaction of optically active substrates leads to the optically active
Mild and Efficient Synthesis of (<i>Z</i>)-α-Chloroalkylidene-β-lactones via the PdCl<sub>2</sub>-Catalyzed Cyclocarbonylation of 2-Alkynols
作者:Shengming Ma、Bin Wu、Shimin Zhao
DOI:10.1021/ol0357245
日期:2003.11.1
A mild and efficient methodology involving PdCl2-catalyzed cyclocarbonylation of 2-alkynols with CuCl2 for the synthesis of (Z)-alpha-chloroalkylidene-beta-lactones was developed. Using the readily available optically active propargylic alcohols allows convenient synthesis of the corresponding (Z)-alpha-chloroalkylidene-beta-lactones with high ee values. cis-Chloropalladation was observed as the major pathway, which is unique as compared to the reported data.