63024-86-2Relevant articles and documents
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.
Reactions of transition-metal nucleophiles with transition-metal efectrophiles. Reactions of acyliron, acylnickei, and cobalt carbonyl anions with (π-Allyl)palladium compieies
Hegedus, Louis S.,Tamura, Rui
, p. 1188 - 1194 (2008/10/08)
(π-Allyl)palladium chloride complexes react with anionic acyiiron tetracarbonyl complexes and anionic acylnickel carbonyl complexes to produce α,α- and β,γ-unsaturated ketones, resulting from acylation of the π-allyl ligand. A variety of π-allyl complexes and acylmetal complexes were studied. Pailadium(II) complexes, including (π-allyl)palladium halides, catalyzed the carbomethoxylation of allyl acetates by NaCo(CO)4. The key step in all of these reactions was thought to be nucleophilic attack of the anionic metal carbonyl complex on a (π-allyl)palladium species.
