title: Generation of allenic/propargylic zirconium complexes and subsequent cross-coupling reactions: a facile synthesis of multisubstituted allenes.
abstract: The beta-alkoxide elimination reaction of propargylic ether with Negishi reagent leads to allenes and/or alkynes after hydrolysis. The product distribution is highly dependent on the substitution pattern of starting propargylic ethers; that is, aryl- or alkyl-substituted propargylic ethers favor the allene products, whereas TMS-substituted propargylic ethers afford alkynes. DFT calculations revealed that both the large steric effect and the beta-effect of the TMS group favor the alkyne products, reversing the selectivity. Subsequent coupling reactions of the allenic/propargylic zirconium intermediates with aryl iodides in the presence of Pd(PPh(3))(4)/CuCl provide a straightforward route for the synthesis of multisubstituted allenes.
authors.affiliation: State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, People's Republic of China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Fu
authors.forename: Jingjin
authors.initials: J
authors.lastname: Chen
authors.forename: Erjuan
authors.initials: E
authors.lastname: Wang
authors.forename: Yuanhong
authors.initials: Y
authors.lastname: Liu
authors.forename: Yuxue
authors.initials: Y
authors.lastname: Li