Different mechanisms have been proposed for the cyclization of enynes catalyzed by electrophilic metal halides or complexes. We present evidence to indicate that the previously reported “carbohydroxypalladation” and the “hydroxycyclization catalyzed by PtII” are closely related reactions. Thus, palladium complexes formed in situ from PdCl2 and trisulfonated phosphane TPPTS or cyclic phosphite P(OCH2)3CEt
Catalytic, Nucleophilic Allylation of Aldehydes with 2-Substituted Allylic Acetates: Carbon–Carbon Bond Formation Driven by the Water–Gas Shift Reaction
作者:Scott E. Denmark、Zachery D. Matesich
DOI:10.1021/jo501004j
日期:2014.7.3
The ruthenium-catalyzedallylation of aldehydes with allylic acetates has been expanded to incorporate substituents at the 2-position of the allylic components. Allylic acetates bearing a variety of substituents (CO2-t-Bu, COMe, Ph, CH(OEt)2, and Me) undergo high-yielding additions with aromatic, α,β-unsaturated, and aliphatic aldehydes. The conditions of the reaction were found to be mild (75 °C,
A new type of catalysis by copper(<scp>I</scp>) salts in the Barbier-type aldehyde allylation with tin(<scp>II</scp>) chloride. Short syntheses of (±)-lavandulol and its γ, δ-dihydro derivative
作者:Toshiro Imai、Shinya Nishida
DOI:10.1039/c39940000277
日期:——
Copper(I) halides and cyanide catalyse the Barbier-type aldehyde allylation with allylation with allylic bromides, chlorides or sulfonates and tin(II) chloride enabling the reaction to take place under very mild conditions with high efficiency.
Indium mediated allylation and propargylation reactions of dimethyl acetals and ketals
作者:Jin Sun Kwon、Ae Nim Pae、Kyung Il Choi、Hun Yeong Koh、Youseung Kim、Yong Seo Cho
DOI:10.1016/s0040-4039(01)00042-9
日期:2001.3
Indium mediated allylation and propargylation reactions of acetals and ketals with various allyl or propargyl bromides in aqueousmedia successfully provided the corresponding homoallylic or homopropargylic (and allenylic) alcohol, respectively, in moderate to good yields. Highly chemoselectiveallylation is also described. The ketal and aryl acetal could be selectively allylated over the aliphatic
Allyl-, Allenyl-, and Propargyl-Transfer Reactions through Cleavage of CC Bonds Catalyzed by an N-Heterocyclic Carbene/Copper Complex: Synthesis of Multisubstituted Pyrroles
作者:Masahiro Sai、Hideki Yorimitsu、Koichiro Oshima
DOI:10.1002/anie.201100631
日期:2011.3.28
Cat. in the bag: The pictured copper complex can promote CC bond cleavage through retro‐allylation of homoallyl alcohols to form allylcopper species. This process is applicable to catalytic allylation of aldehydes and imines with homoallyl alcohols. The method has also been extended to regioselective allenylation and propargylation of imines.