Cyclizations in the Addition of Alkylmercury Halides to Dienes and Enynes
作者:Glen A. Russell、Chaozhong Li、Ping Chen
DOI:10.1021/ja9601898
日期:1996.1.1
or CH2CHC(O)OC(Me)2CHCH2. The radicals t-BuCH2CH•C(O)C(Me)2(CH2)nCHCH2 cyclize mainly in the 6-endo mode for n = 1 and more rapidly in the 6-exo mode for n = 2, while the radicals t-BuCH2CH•C(O)OC(Me)2(CH2)nCHCH2 cyclize only in the exo mode for n = 0 or 1 but with a faster rate for 5-exo-cyclization. Gem-dimethyl substitution adjacent to the alkyl oxygen accelerates the 5-exo-cyclization of the ester
将叔丁基卤化汞光刺激加成到 1,6-二烯和烯炔,包括 (CH2CHCH2)2X,其中 X = CH2、C(COEt)2、O 或 NCH2CHCH2,形成由 5-外环化产生的初级烷基卤化汞加合物自由基,t-BuCH2CH•CH2XCH2CHCH2。这些自由基过程的动力学链长度很低,在 Me2SO 中 35 °C 时的范围为 3-7。在光刺激下将 t-BuHgI 添加到 CH2CHP(O)(OR)OCH2CHCH2(R = H 或烯丙基)、CH2CHC(O)N(R)CH2CHCH2(R = Me、Ph 或 CH2CHCH2) 或 CH2CHC(O)OC(Me)2CHCH2。基团 t-BuCH2CH•C(O)C(Me)2(CH2)nCHCH2 在 n = 1 时主要以 6-endo 模式环化,在 n = 2 时以 6-exo 模式更快地环化,而基团 t-BuCH2CH•C(O)OC(Me)2(CH2)nCHCH2
Aruncin B: Synthetic Studies, Structural Reassignment and Biological Evaluation
作者:Aubert Ribaucourt、Christopher Towers、Laia Josa-Culleré、Frances Willenbrock、Amber L. Thompson、David M. Hodgson
DOI:10.1002/chem.201702949
日期:2017.11.21
the recently isolated cytotoxin aruncin B (1), as well as to the sodium salt Z-34 of a related ethyl ether regioisomer; however, none of their corresponding free acids could be obtained. Their acid sensitivity, together with detailed analysis of the spectroscopic data indicated that profound structural revision was necessary. This led to reassignment of aruncin B as a Z-γ-alkylidenebutenolide Z-36. Although
针对最近分离的细胞毒素 aruncin B (1) 最初提出的结构的钠盐 E- 和 Z-25 以及钠盐建立了闭环烯烃复分解 (RCM)/氧硒化-氧化硒消除序列相关乙醚区域异构体的Z-34;然而,没有获得它们相应的游离酸。它们的酸敏感性以及光谱数据的详细分析表明,需要进行深入的结构修正。这导致 aruncin B 被重新指定为 Z-γ-亚烷基丁烯内酯 Z-36。虽然相关的RCM/氧化硒化-氧化硒消除序列被用来确认γ-亚烷基丁烯内酯基序,但随后开发了β-碘Morita-Baylis-Hillman反应/Sonogashira交叉偶联-5-exo-dig内酯化序列,因为其简洁性和多样化的灵活性。Aruncin B (36) 与 14 种 γ-亚烷基丁烯内酯类似物一起生成用于生物学评价。
γ-Lactone Formation in the Addition of Benzenesulfonyl Bromide to Diene and Enyne Esters
作者:Chen Wang、Glen A. Russell
DOI:10.1021/jo982388a
日期:1999.3.1
The gem-dialkyl effect has been used to promote the formation of functionalized gamma-lactones in the addition of benzenesulfonyl bromide to diene and enyne esters. Introduction of 3 mol % of pyridine into the reactions increases the yields of lactones produced from tertiary esters. Formation of the C-alpha-C-beta bond of gamma-lactones has been achieved in both C-alpha-->C beta and C-beta-->C-alpha radical cyclization directions.