formal synthesis of (+)-neovibsanin B has been achieved by a sequence that applies an asymmetric 1,4-addition of (H2C═CH)2Cu(CN)Li2 to trisubstituted α,β-carboxylic acid derivative 1 to induce the chirality at the C-11 all-carbon quaternary center. Together with a modified Negishi cyclic carbopalladation-carbonylative esterificationtandemreaction for constructing the A-ring, the synthesis was completed
通过将(H 2 C + CH)2 Cu(CN)Li 2不对称地1,4-加成到三取代的α,β-羧酸衍生物上的序列,实现了对(+)-新诺布沙宁B的对映体控制形式合成。1在C-11全碳四元中心诱导手性。与用于构建A环的改良的Negishi环状碳环羰基化-羰基化酯化串联反应一起,完成了合成。
Ester Formation via Symbiotic Activation Utilizing Trichloroacetimidate Electrophiles
作者:Nivedita S. Mahajani、Rowan I. L. Meador、Tomas J. Smith、Sarah E. Canarelli、Arijit A. Adhikari、Jigisha P. Shah、Christopher M. Russo、Daniel R. Wallach、Kyle T. Howard、Alexandra M. Millimaci、John D. Chisholm
DOI:10.1021/acs.joc.9b00745
日期:2019.6.21
Trichloroacetimidates are useful reagents for the synthesis of esters under mild conditions that do not require an exogenous promoter. These conditions avoid the undesired decomposition of substrates with sensitive functional groups that are often observed with the use of strong Lewis or Brønsted acids. With heating, these reactions have been extended to benzyl esters without electron-donating groups. These inexpensive