35281-61-9Relevant academic research and scientific papers
Studies on Cu(I)-catalyzed synthesis of simple 3-substituted 1,2-allenes and optically active 2-substituted secondary 2,3-allenols
Li, Jing,Zhou, Chao,Fu, Chunling,Ma, Shengming
experimental part, p. 3695 - 3703 (2009/09/05)
The sequential treatment of terminal alkynes or propargylic alcohols with n-BuLi and MOMCl afforded the corresponding propargylic methyl ethers, which would react with primary alkyl Grignard reagents under the catalysis of CuBr to afford 3-substituted 1,2-allenes or 2-substituted secondary 2,3-allenols, respectively. The reaction may be applied to the synthesis of optically active 2-substituted secondary 2,3-allenols with up to >99% ee without any protection to the free hydroxyl group in the starting 4-hydroxy-2-alkynyl methyl ethers.
A short synthesis of α-allenic alcohols from α,β-unsaturated carbonyl compounds with dichloromethyl p-tolyl sulfoxide
Satoh, Tsuyoshi,Noguchi, Takafumi,Miyagawa, Toshifumi
, p. 5689 - 5692 (2008/12/22)
The reaction of the α-sulfinyl carbanion of dichloromethyl p-tolyl sulfoxide with α,β-unsaturated carbonyl compounds gave 1-chlorocyclopropyl p-tolyl sulfoxides having a carbonyl group in good to high yields. The carbonyl groups in the products were reduced or treated with alkylmetals to give alcohols. Finally, the alcohols were treated with Grignard reagent to give α-allenic alcohols via the rearrangement of the cyclopropylmagnesium carbenoid intermediates, which were generated by the sulfoxide-magnesium exchange reaction, in good to high yields. This procedure provides a new method for a short synthesis of various α-allenic alcohols in two or three steps from relatively easily available α,β-unsaturated carbonyl compounds.
Regio- and diastereoselective allenylation of aldehydes in aqueous media: Total synthesis of (+)-goniofufurone
Yi, Xiang-Hui,Meng, Yue,Hua, Xiao-Gang,Li, Chao-Jun
, p. 7472 - 7480 (2007/10/03)
The regio- and diastereoselectivities of metal-mediated allenylation of carbonyl compounds were investigated in aqueous media. Different metal mediators showed varied regioselectivities on product formation during propargylation-allenylation reactions of carbonyl compounds with simple propargyl bromide. Under the standard reaction conditions, the use of indium provided the highest regioselectivity, with a preference of formation of the homopropargyl alcohol. The use of tin and bismuth as the metal mediator provided slightly lower selectivities with the same preference. The use of zinc and cadmium as the mediators further lowered the product selectivity. The reactions of an alipathic aldehyde with simple propargyl bromide showed a lower selectivity than the reaction of an aromatic aldehyde in most cases, except for the use of tin or zinc (where comparable selectivities were observed). On the other hand, the reaction of terminal-substituted propargyl bromides with aldehydes mediated by indium showed a high regioselectivity in forming allenylation products. The indium-mediated allenylation of carbonyl compounds bearing an α-hydroxyl group also proceeded with a high diastereoselectivity, forming syn-diols predominantly in aqueous ethanol. The high diastereoselectivity in allenylation of α-hydroxyl-substituted aldehydes was attributed to the chelation effect exhibited by the α-hydroxyl substituent. Through the use of this highly diastereoselective allenylation, (+)-goniofufurone was synthesized from D'-glucurono-6,3-lactone.
