Artemisinin tricyclic analogs: Role of a methyl group at C-5a
摘要:
New artemisinin tricyclic analogs, bearing a methyl group at C-5a were synthetized through ozonation of vinylsilanes. Presence of such a substituent was detrimental to the antimalarial activity of these trioxanes, thus reinforcing the hypothesis that tight hemin-trioxane complexes are involved in the activation phase of these compounds. (C) 1998 Elsevier Science Ltd. All rights reserved.
Synthetic Studies of Antitumor Macrolide Rhizoxin: Stereoselective Syntheses of the C(1)−C(9) and C(12)−C(26) Subunits
作者:Steven D. Burke、Jian Hong、Joseph R. Lennox、Andrew P. Mongin
DOI:10.1021/jo980754k
日期:1998.10.1
Horner-Wadsworth-Emmons reaction. The central segment 4 and the oxazole chromophore side chain 3 were coupled using another highlystereoselectiveHorner-Wadsworth-Emmonsreaction. Two different lactone subunits [C(1)-C(9) segment 5 and C(3)-C(10) segment 47] were also prepared, employing a thermodynamically controlled diastereotopic group differentiation tactic for establishing the C(5) stereochemistry
Reaction of Trialkyl(dibromomethyl)silanes or 1,2-Bis(dibromomethyl)benzene with Triorganomanganates. A Facile and Selective Synthesis of Alkenylsilanes and 1,2-Diaryl-1,2-dihydrobenzocyclobutenes
stereoselectivity in good yields. The reaction of trialkyl(dibromomethyl)silanes with alkylmagnesium halides proceeded in the presence of a catalytic amount of manganese(II) chloride. Treatment of 1,2-bis(dibromomethyl)benzene with triphenylmanganate gave 1,2-diphenyl-1,2-dihydrobenzocyclobutene.
用衍生自氯化锰 (II) 和三摩尔量的格氏试剂或烷基锂的三烷基锰酸盐处理三烷基(二溴甲基)硅烷,以良好的收率提供具有高立体选择性的(E)-1-三烷基甲硅烷基-1-烯烃。三烷基(二溴甲基)硅烷与烷基卤化镁的反应在催化量的氯化锰(II)存在下进行。用三苯基锰酸盐处理 1,2-双(二溴甲基)苯得到 1,2-二苯基-1,2-二氢苯并环丁烯。
Synthesis of (+)-dihydrocompactin and (+)-compactin via vinylsilane terminated cationic cyclization
作者:Steven D. Burke、David N. Deaton
DOI:10.1016/s0040-4039(00)92272-x
日期:1991.1
described, featuring cationic polyene cyclization mediated by a vinylsilane terminating group and a benzenedimethanol acetal initiator. Further transformations resulting in formal and total syntheses of (+)-compactin and (+)-dihydrocompactin, respectively, are also reported.
tert-Butyldimethylsilyldihalomethyllithium as a dihalomethylene dianion synthon. 1,3-Rearrangement and 1,4-rearrangement of silyl group from carbon to oxide
One-pot synthesis of R1CH(OSiMe2-t-Bu)CX2CH(OH)R2 (X=Cl, Br) successive addition of two different aldehydes (R1CHO and R2CHO) has been achieved starting from tert-butyldimethylsilyldihalomethyllithium. Treatment of a THF solution of the title carbanion (X=Cl) with p-MeOC6H4CHO or n-BuCHO followed by an addition of HMPA and benzaldehyde gave the corresponding 1,3-diol monosilyl ether in 83% or 45% yield
Olefination of carbonyl compounds with gem-dizincioalkanes, bis(iodozincio)methane, 1,1-bis(iodozincio)ethane, and bis(bromozincio)methyltrimethylsilane, afforded the corresponding olefins in good to excellent yields.