Unexpected SN2′-type addition–elimination reactions of 1-aryl-2,3-allenols with LiX. Synthesis and synthetic application of 1-aryl-3-halo-1,3-dienes
摘要:
1-Aryl-3-halo-1,3-dienes were prepared from the sequential addition-elimination reaction of 1-aryl-2,3-allenols with LiX (X = Br, Cl) in HOAc in moderate to good yields. Here the aromatic substituent is crucial to this interesting transformation since no reaction was observed with 1-alkyl or perfluoroalkyl-2,3-allelols. The 1-aryl-3-halo-1,3-dienes prepared can be used as Useful partners in Diels-Alder reactions with dienophiles leading to polycyclic quinone derivatives, (C) 2002 Elsevier Science Ltd. All rights reserved.
electrophiles. The effortlessness of C−C bond formation, mild reaction conditions, neither catalysts nor light irradiation, and exquisite selectivity, both in terms of functional‐group tolerance and chemo‐, site‐, and stereo‐selectivity, converts this trifluorosulfonylation‐rearrangement sequence into an appealing protocol for the preparation of novel functionalized enones. The synthetic utility of this
Barbier-type propargylation of carbonyl compounds with propargyl bromide has been achieved with reactive zinc–copper couple under solvent-free conditions. The reaction of aldehydes with propargyl bromide produced the unique homopropargyl alcohols in excellent yields at room temperature without the formation of homoallenyl alcohols. The ketones reacted with propargyl bromide to give the corresponding homopropargyl
Reversal of the benzophenone reactivity upon η5-complexation to bis (η-cyclopentadienyl) zirconium
作者:Frank Rosenfeldt、Gerhard Erker
DOI:10.1016/s0040-4039(00)77773-2
日期:1980.1
Reversal of the carbonyl activity of benzophenone, serving as electron donor in single-electron transfer processes and acting as a proton acceptor through the ‘carbonyl’ carbon atom, is observed upon η2-complexation to zirconocene.
Radikalische reaktionswege bei thermisch induzierten umsetzungen von zirconocenkomplexen
作者:G. Erker、F. Rosenfeldt
DOI:10.1016/0040-4020(82)85115-6
日期:1982.1
The formation of products 2, 3 and 4 (a–l) from both the reaction of η2-benzophenone zirconocene 1 with alkyl halides and the thermolysis of the α-(Cp2ZrCl)-substituted benzhydrylmethylether 9, the latter proceeding with anchimericassistance of the metal, can be understood assuming a stepwise reaction path through radical intermediates. The proposed intermediate transition-metal benzophenone ketyl
Regioselective Propargylation of Aldehydes and Ketones by Electrochemical Reaction using Zinc and Aluminum Anodes
作者:Nobuhito Kurono、Kazuya Sugita、Masao Tokuda
DOI:10.1016/s0040-4020(99)01089-3
日期:2000.2
Electrochemical propargylation of aldehydes and ketones with unsubstituted or α-substituted propargylic bromides using platinum cathode and zinc anode proceeded efficiently under mild conditions to give the corresponding homopropargyl alcohols exclusively in high yields. Similar electrochemical propargylation with γ-substituted propargyl bromides gave the corresponding homoallenyl alcohols as major