One-Pot, Three-Step Synthesis of Cyclopropylboronic Acid Pinacol Esters from Synthetically Tractable Propargylic Silyl Ethers
作者:Jonathan A. Spencer、Craig Jamieson、Eric P. A. Talbot
DOI:10.1021/acs.orglett.7b01778
日期:2017.7.21
propargylic silyl ethers can be converted to complex cyclopropylboronic acid pinacol esters in an efficient one-pot procedure. Terminal acetylenes undergo a Schwartz’s reagent catalyzed hydroboration; subsequent addition of further Schwartz’s reagent and Lewis acid-mediated activation of neighboring silyl ether allows cyclization to access a range of cyclopropylboronic acid pinacol esters. The scope includes
Gold‐Catalyzed Dehydrogenative Cycloisomerization of 1,4‐Enyne Esters to 3,5‐Disubstituted Phenol Derivatives
作者:Cuili Chen、Xianxiao Chen、Xiaoxiang Zhang、Shifa Wang、Weidong Rao、Philip Wai Hong Chan
DOI:10.1002/adsc.201701068
日期:2017.12.19
dehydrogenative cycloisomerization of 1,4‐enyne esters in the presence of 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) or N‐fluorobenzenesulfonimide (NFSI) is described. The synthetic versatility of the methodology was exemplified by a gram‐scale reaction of one example, the ease to realize subsequent functional transformations of an adduct, and the application of the method to the synthesis of the bioactive
N-Vinylpyridinium tetrafluoroborate salts as reagents for the stereoselective and regioselective synthesis of symmetrical (2E,4E)-1,6-dioxo-2,4-dienes
作者:Ge Gao、Neil Brown、Machiko Minatoya、Keith R. Buszek
DOI:10.1016/j.tetlet.2008.08.076
日期:2008.11
in Pd(0)-catalyzed Suzuki cross-couplingreactions with aryl and vinyl boronic acids. We now report that these crystalline, air-stable, and non-hygroscopic salts are also useful reagents for the synthesis of symmetrical (2E,4E)-1,6-dioxo-2,4-dienes (diene diones), which in turn are valuable starting materials for the synthesis of various five-membered heterocycles. The optimization of reaction conditions
A Convergent, Stereoselective Route to Trisubstituted Alkenyl Boronates
作者:Jean Michalland、Samir Z. Zard
DOI:10.1021/acs.orglett.1c03022
日期:2021.10.15
A modular, stereoselectiveroute to trisubstituted (Z)-alkenyl (MIDA)boronates is described, consisting of the radical addition–fragmentation of dithiocarbonates to 2-(MIDA)boronyl-3-(2′-fluoro-pyridyl-6′-oxy)-alkenes. The bulky (MIDA)boronate ensures a highly stereoselective fragmentation that is enhanced by the poor stabilization of the radical adjacent to the tetravalent boron atom. The vinyl boronate
Axial-to-Central Chirality Transfer for Construction of Quaternary Stereocenters via Dearomatization of BINOLs
作者:Xiao-Long Min、Xu-Ran Xu、Ying He
DOI:10.1021/acs.orglett.9b03558
日期:2019.11.15
All-carbonquaternary stereocenters are versatile building blocks, and their asymmetric construction has attracted much attention. Herein, we disclose an axial-to-central chirality transfer strategy for the synthesis of chiralquaternary stereocenters via dearomatization of (S)-BINOLs. The reaction proceeded smoothly with a wide range of propargyl carbonates to afford chiral spiro-compounds in high