Stereoselective Ring Expansion of Vinyl Oxiranes: Mechanistic Insights and Natural Product Total Synthesis
作者:Matthew Brichacek、Lindsay A. Batory、Jon T. Njardarson
DOI:10.1002/anie.200906830
日期:2010.2.22
applicable, catalytic, and stereoselective vinyl oxirane ringexpansion is described (see scheme; hfacac=hexafluoroacetylacetonate). The stereoselectivity was influenced by several reaction parameters, and kinetic studies support a mechanistic proposal involving the in situ formation of a more reactive catalytic species. This ring‐expansion reaction has been employed in the asymmetric total synthesis
Highly general synthesis of [E]- and [Z]-3-alkylsubstituted allylboronates via one-carbon homologation of stereospecific 1-alken-1-ylboronates
作者:Herbert C. Brown、Avinash S. Phadke、Narayan G. Bhat
DOI:10.1016/s0040-4039(00)61491-0
日期:1993.12
Stereospecific 1-alken-1-ylboronates readily react with in situ generated chloromethyllithium, producing the corresponding allylboronate in good yields and in excellent stereochemical purities. These are very important synthetic intermediates and conversion of a representative derivative, [E]-2-(2-heptenyl)-1,3,2-dioxaborinane, 2 (R1 = C4H9, R2 = R3 = H), into several compounds of synthetic interest
立体特异性的1-烯-1-基硼酸酯易于与原位生成的氯甲基锂反应,以良好的产率和优异的立体化学纯度产生相应的烯丙基硼酸酯。这些是非常重要的合成中间体,是代表性衍生物[ E ] -2-(2-庚烯基)-1,3,2-二氧杂硼烷2(R 1 = C 4 H 9,R 2 = R 3 = H ),描述了几种具有合成意义的化合物。
Synthesis of (+)-Manoalide via a Copper(I)-Mediated 1,2-Metalate Rearrangement
作者:Agnès Pommier、Viatcheslav Stepanenko、Krzysztof Jarowicki、Philip J. Kocienski
DOI:10.1021/jo0268097
日期:2003.5.1
(+)-(4R)-manoalide is reported in which all 25 carbons of the sesterterpenoid skeleton are constructed from 3-furaldehyde, trimethylalane, oxirane, CO, beta-ionone, and propargyl bromide. The overall yield for the longest linear sequence (12 steps) is 12%. Key steps include (a) a zirconium-catalyzed carboalumination reaction to construct the C10-C11 trisubstituted alkene, (b) a Cu(I)-mediated 1,2-metalate rearrangement