作者:Michael H. Becker、Peter Chua、Robert Downham、Christopher J. Douglas、Neil K. Garg、Sheldon Hiebert、Stefan Jaroch、Richard T. Matsuoka、Joy A. Middleton、Fay W. Ng、Larry E. Overman
DOI:10.1021/ja074300t
日期:2007.10.1
studies toward the complex marine alkaloid sarain A. Various strategies were conceived, setbacks encountered, and solutions developed, ultimately leading to a successful enantioselective totalsynthesis. Our route to (+)-sarain A features a number of key steps, including an asymmetric Michael addition to install the C4'-C3'-C7' stereotriad, an enoxysilane-N-sulfonyliminium ion cyclization to set the C3 quaternary
本文描述了我们对复杂海洋生物碱 sarain A 的合成研究的细节。设想了各种策略、遇到的挫折和开发的解决方案,最终导致对映选择性全合成的成功。我们的 (+)-sarain A 路线具有许多关键步骤,包括不对称迈克尔加成以安装 C4'-C3'-C7' 立体三联体,烯氧基硅烷-N-磺酰亚胺离子环化以设置 C3 季碳立体中心,并组装二氮杂三环十一烷核心、构建13元环的闭环复分解、形成不饱和14元大环的分子内Stille偶联以及叔胺-醛邻近相互作用的后期安装。
Copper bis(oxazolines) as catalysts for stereoselective aziridination of styrenes with N-tosyloxycarbamates
styrenes. Subsequent ring-opening reactions of styrene-derived aziridines at the benzylic position were observed with various oxygen and nitrogen nucleophiles under Lewis acid catalysis affording the corresponding products with complete inversion of stereochemistry. The strategy was used to synthesize the β-blocker, (R)-nifenalol.
作者:David J. Fox、Daniel Sejer Pedersen、Stuart Warren
DOI:10.1039/b606873a
日期:——
α-Diphenylphosphinoyl ketones are selectively and sequentially alkylated at the α-position. Double lithiation and selective alkylation occurs at the less stabilised γ-position. Dephosphinoylation of the alkylation products gives ketones. Mono-alkylation is selective, highly crystalline intermediates are formed and a one-pot strategy is possible. The method is ideally suited for the preparation of acid-sensitive ketones.
Nucleophilic 5-endo-trig cyclization of 2-(trifluoromethyl)allylic metal enolates and enamides: Synthesis of tetrahydrofurans and pyrrolidines bearing exo-difluoromethylene units
作者:Takeshi Fujita、Masahiro Hattori、Masaaki Matsuda、Ryutaro Morioka、Tanner C. Jankins、Masahiro Ikeda、Junji Ichikawa
DOI:10.1016/j.tet.2018.11.011
日期:2019.1
proceeded exclusively in each case to afford the corresponding five-membered heterocycles with both exo-difluoromethylene and exo-alkylidene units. On treatment with potassium hexamethyldisilazide (KHMDS) or lithium diisopropylamide (LDA), 2-(trifluoromethyl)allylic ketones or imines provided the corresponding tetrahydrofurans or pyrrolidines bearing a Z-alkylidene group with perfect or substantial stereoselectivity
undirected para-selective two-step C–H alkylation of complex arenes useful for late-stage functionalization. The combination of a site-selective C–H thianthrenation with palladium-catalyzed reductive electrophile cross-coupling grants access to a diverse range of synthetically useful alkylated arenes which cannot be accessed otherwise with comparable selectivity, diversity, and practicality. The robustness