Asymmetric cyclization–carbonylation of 2-alkyl-2-propargylcyclohexane-1,3-diones: facile access to optically active hydrindanes
摘要:
Oxidative cyclization - carbonylation of 2-alkyl-2-propargylcyclohexane-1,3-diones mediated by Pd(TFA)(2)/2,2'-isopropylidenebis[(4R)4-(3,4-dimethoxyphenyl)-2-oxazoline] 28 afforded bicyclic-beta-alkoxyacrylates in 51 - 74% yields with 72 - 82% ee. The products containing quaternary carbon were converted to optically active hydrindanes 33. (c) 2007 Elsevier Ltd. All rights reserved.
Asymmetric cyclization–carbonylation of 2-alkyl-2-propargylcyclohexane-1,3-diones: facile access to optically active hydrindanes
摘要:
Oxidative cyclization - carbonylation of 2-alkyl-2-propargylcyclohexane-1,3-diones mediated by Pd(TFA)(2)/2,2'-isopropylidenebis[(4R)4-(3,4-dimethoxyphenyl)-2-oxazoline] 28 afforded bicyclic-beta-alkoxyacrylates in 51 - 74% yields with 72 - 82% ee. The products containing quaternary carbon were converted to optically active hydrindanes 33. (c) 2007 Elsevier Ltd. All rights reserved.
asymmetric cyclization–carbonylation of propargyl ketols catalyzed by palladium(II) with chiral bisoxazoline (box) ligands. The 2S,3S enantiomer of (±)-6 was preferentially converted to 13 (45–49% yields, 37–46% ee), and the 2R,3R enantiomer of (±)-6 was preferentially converted to 14 (21–23% yields, 92–97% ee). As an application of this reaction, formal synthesis of (+)-bakkenolide A was achieved.