Stereoselective synthesis of allylic boronates via palladium-catalyzed cross-coupling reaction of Knochel's (dialkoxyboryl) methylzinc reagents with 1-halo-1-alkenes
作者:Takeo Watanabe、Norio Miyaura、Akira Suzuki
DOI:10.1016/0022-328x(93)83081-6
日期:1993.2
The cross-coupling reaction of (dialkoxyboryl)methylzinc reagents IZnCH2B(OR)2 with 1-halo-1-alkenes was catalysed by triphenyl-phosphine- or triphenylarsine-based palladium complexes to provide esters of stereodefined allylboronic acids with stereoselectivity. The reaction was applied to provide a cyclic alcohol via the first intramolecularallylboration of carbonyl.
Development of the “Diverted Heck” Reaction for the Synthesis of Five-Membered Rings
作者:Kevin Breitwieser、Peter Chen
DOI:10.1021/acs.organomet.1c00025
日期:2021.3.22
The “diverted Heck” reaction has been shown to be a potent method to synthesize cyclopropanes from electron-rich olefins and iodomethyl trifluoroborate. Nevertheless, it is not mechanistically limited to the three-membered rings. The synthesis of five-membered rings using bifunctional substrates with a halide moiety and an organometallic group is described. Furthermore, the reactions of the respective
Cornforth–Evans Transition States in Stereocontrolled Allylborations of Epoxy Aldehydes
作者:Robert R. A. Freund、Matthias Borg、Daniel Gaissmaier、Robin Schlosser、Timo Jacob、Hans‐Dieter Arndt
DOI:10.1002/chem.202001479
日期:2020.7.14
(CE) model for alkoxy‐ and epoxy‐substitutedaldehydes. CE‐type transition states were uniformly identified as minima in advanced, DFT‐based computational studies of allylboration reactions of epoxy aldehydes, conforming well to the experimental data, and highlighting the underestimated relevance of this model. Furthermore, a mechanism‐based rationale for the substitution pattern of the epoxide was delineated
Iridium-Catalyzed Enantioconvergent Allylation of a Boron-Stabilized Organozinc Reagent
作者:Panchi Guo、Miao Zhan
DOI:10.1021/acs.joc.1c01076
日期:2021.7.16
An iridium-catalyzed enantioconvergent coupling of the versatile boron-stabilized organozinc reagent BpinCH2ZnI with a racemic branched allylic carbonate has been developed here, which differs from our previous work by using 1,1-bisborylmethane through the kinetic resolution process. The reaction has a broad substrate scope, and various chiral homoallylic organoboronic esters could be obtained in good
Stereoselective total synthesis of parthenolides indicates target selectivity for tubulin carboxypeptidase activity
作者:Robert R. A. Freund、Philipp Gobrecht、Zhigang Rao、Jana Gerstmeier、Robin Schlosser、Helmar Görls、Oliver Werz、Dietmar Fischer、Hans-Dieter Arndt
DOI:10.1039/c9sc01473j
日期:——
aldehydes was established to enable stereoselective access to α-(exo)-methylene γ-butyrolactones under mild conditions. Acid-labile functionality and chiral carbonyl compounds are tolerated. Excellent asymmetric induction was observed for β,β′-disubstituted α,β-epoxy aldehydes. These findings led to the enantioselective total synthesis of the sesquiterpene natural product (−)-parthenolide, its unnatural