Oxidative Heck Vinylation for the Synthesis of Complex Dienes and Polyenes
摘要:
We introduce an oxidative Heck reaction for selective complex diene and polyene formation. The reaction proceeds via oxidative Pd(II)/sulfoxide catalysis that retards palladium-hydride isomerizations which previously limited the Heck manifold's capacity for furnishing stereodefined conjugated dienes. Limiting quantities of nonactivated terminal olefins (1 equiv) and slight excesses of vinyl boronic esters (1.5 equiv) that feature diverse functionality can be used to furnish complex dienes and polyenes in good yields and excellent selectivities (generally E:Z = >20:1; internal:terminal = >20:1). Because this reaction only requires prior activation of a single vinylic carbon, improvements in efficiency are observed for synthetic sequences relative to ones featuring reactions that require activation of both coupling partners.
AgSbF<sub>6</sub>-Catalyzed <i>anti</i>-Markovnikov hydroboration of terminal alkynes
作者:Ramesh Mamidala、Vipin K. Pandey、Arnab Rit
DOI:10.1039/c8cc07499b
日期:——
AgSbF6-Catalyzed anti-Markovnikov addition of pinacolborane (HBpin) to terminal alkynes to produce the E-vinylboronates is reported. This efficient methodology is scalable, compatible with sterically and electronically diverse alkynes, and works at room temperature under solvent-free condition. The utility of this method is demonstrated in the facilesynthesis of the clinically important (E)-2,4,3′
Synthesis of Functionalized Vinyl Boronates via Ruthenium-Catalyzed Olefin Cross-Metathesis and Subsequent Conversion to Vinyl Halides
作者:Christie Morrill、Robert H. Grubbs
DOI:10.1021/jo0345345
日期:2003.7.1
using ruthenium-catalyzed olefin cross-metathesis of 1-propenyl pinacol boronate and various alkenes, including functionalized and 1,1-disubstituted alkenes. The resultant boronate cross products are stereoselectively transformed into predominantly Z-vinyl bromides and E-vinyl iodides. The vinyl bromides may be synthesized in a two-step, one-pot synthesis from a variety of olefins, resulting in a Z-selective
E/Z-Selectivity Controlled by Participation of Internal Oxy Group During Electrophilic Substitution of Alk-1-enylboronate with Bis(2,4,6-trimethylpyridine)iodonium Salt
observed in electrophilic iodo-substitution of 4-benzoyloxybut-1-enylboronate using bis(2,4,6-trimethylpyridine)iodine(I) salt, rationalized by participation of the internal benzoyloxy group. Stereospecific inversion of configuration was observed in electrophilic iodo-substitution of 4-benzoyloxybut-1-enylboronate using bis(2,4,6-trimethylpyridine)iodine(I) salt, rationalized by participation of the internal
<scp>Copper‐Catalyzed</scp> Highly Stereoselective Hydrodifluoroallylation of Cyclopropenes and Alkenyl Boronates with 3,<scp>3‐Difluoroallyl</scp> Sulfonium Salts<sup>†</sup>
作者:Xing Gao、Xiaoxiao Ren、Wei Deng、Xingang Zhang
DOI:10.1002/cjoc.202300436
日期:2023.12.15
asymmetric fluoroalkylation with ubiquitous alkenes. The advantages of this protocol are synthetic convenience, high functional group tolerance, and the synthetic versatility of the resulting gem-difluoroallyl cyclopropanes and borylalkanes. The synthetic utility of this approach has also been demonstrated by the diversified transformations of the gem-difluoroallylated products and the rapid synthesis of bioactive