Phosphine Catalyst-Controlled Cycloaddition or Dienylation Reactions of Trifluoromethyl Aryl Ketones with Bis-Substituted Allenoates
作者:Hua Xiao、Zhuo Chai、Ri-Sheng Yao、Gang Zhao
DOI:10.1021/jo401462c
日期:2013.10.4
A chemoselective phosphine-catalyzed cyclo-addition or dienylation reaction between trifluoromethyl-substituted ketones and bis-substituted allenoates was described. Under the catalysis of triarylphosphine, the reaction gave a range of trifluoromethylated tetrahydrofurans with broad substrate tolerance and good to excellent stereo-selectivity, while the use of trialkylphosphine switched the reaction pathway to furnish CF3-substituted dienyl tertiary alcohols, chemoselectivey. Moreover, a preliminary study on the asymmetric version of the reaction was also performed, which represents the first example of a phosphine-catalyzed asymmetric reaction between allenoates and carbonyl compounds.
PPh3-Mediated [3+2] Cycloaddition Reaction between Bis-Substituted Allenoate and N-Tosylaldimines to Construct 2-Pyrrolines
A triphenylphosphine-promoted [3+2] cycloaddition of α,γ-bis-substituted allenoates and N-tosylaldimines followed by alkene isomerization was disclosed, affording a series of functionalized 2-pyrroline derivatives in moderate chemical yields with random diastereoselectivities.
Phosphine-Mediated Stereoselective Reductive Cyclopropanation of α-Substituted Allenoates with Aromatic Aldehydes
作者:Silong Xu、Lili Zhou、Renqin Ma、Haibin Song、Zhengjie He
DOI:10.1021/ol902747c
日期:2010.2.5
cyclopropanation between α-substituted allenoates2 and aldehydes 1 is described. It represents a new member of the allene-based annulations, which provides facile and efficient access to highly functionalized cyclopropanes 3 from simple and readily available starting materials. It also unveils an unprecedented reactivity pattern of allenoates with aldehydes.