The flow thermolyses of 1-isobutenyl alkynyl- and 2-methylphenyl alkynyl ketones. Synthesis of methylenomycin B
作者:Manuel Roller、Martin Karpf、André S. Dreiding
DOI:10.1016/s0040-4039(00)83928-3
日期:1986.1
lead to phenols and to cyclopentenones. The results are explained by a 5-ring carbene process (the known α-alkynone cyclization) and a 6-ring as well as a 5-ring addition process. The latter two (novel) processes are thought to be intramolecular “CH to CC additions” in two directions. The 5-ring addition process was used in a short (but low yield) synthesis of methylenomycinB.
Palladium-Catalyzed Cyclization of 1-Iodo-Substituted 1,4-, 1,5-, and 1,6-Dienes as Well as of 5-Iodo-1,5-dienes in the Presence of Carbon Monoxide
作者:Ei-ichi Negishi、Shengming Ma、John Amanfu、Christophe Copéret、Joseph A. Miller、James M. Tour
DOI:10.1021/ja9533205
日期:1996.1.1
homoallyl-, and higher ω-alkenylmetalation reactions of alkynes involving Zn, Al−Zr, Zn−Zr, and Cu, (b) trans-hydroalumination and Cu-catalyzed trans-carbomagnesiation of propargyl alcohols, and (c) Zr-promoted alkyne−alkene coupling. Various factors affecting three cyclic acylpalladation (Types I−III Ac-Pd) and three cycliccarbopalladation (Types I−III C-Pd) processes of the ω-alkene-containing alkenyl
一系列含 ω-烯烃的烯基碘化物是通过 (a) 涉及 Zn、Al-Zr、Zn-Zr 和 Cu 的炔烃的各种烯丙基-、高烯丙基-和更高 ω-烯基金属化反应制备的,(b) 反式-炔丙醇的加氢铝化和 Cu 催化的碳镁转移,以及(c)Zr 促进的炔烃偶联。在CO和Pd-膦催化剂的影响下,影响含ω-烯烃的链烯基碘化物的三环酰基钯化(I-III型Ac-Pd)和三环碳钯化(I-III型C-Pd)过程的各种因素已被研究划定。在甲醇或其他醇的存在下,在相对较高的 CO 压力(30-100 个大气压)下(条件 IV),含有五元酮的 II 型 Ac-Pd 产品,例如 22、26-28、30 和 32,一般可以高收率获得。产生五元环的各种羰基化环化反应的速率顺序如下:内酯化 > II 型 Ac-Pd 反应 > C-烯醇被丙二酸阴离子捕获。预...
Novel 1-phosphonyl radicals derived from 1-mono and 1,1-di-heterosubstituted 2-oxoalkylphosphonates as useful phosphoroorganic intermediates in organic synthesis
作者:Piotr Balczewski
DOI:10.1016/s0040-4020(96)01122-2
日期:1997.2
Novel 1-phosphonyl radicals 17 were obtained from 1-mono(Y=H, X=Cl, Br, SMe) and 1.1-di (Y=X=Cl) hetero substituted 2-oxoalkylphosphonates 16 under the reductive conditions () and utilized in the reactions with alkenes for the free-radical synthesis of highly functionalizedphosphonates 19 and 20. The utility of the new approach has been demonstrated by the synthesis of methylenomycin B 13, a cyclopentanoid
Fittig bislactones in cyclopentenone synthesis: short synthesis of methylenomycin B
作者:George M. Strunz、G. Sankar Lal
DOI:10.1139/v82-363
日期:1982.10.15
di-γ-lactone, with methyllithium, followed by alkali, afforded 5-carboxymethyl-2,3-dimethylcyclopent-2-en-1-one. This compound on decarboxylation with lead tetraacetate afforded the antibiotic methylenomycinB.