The copper-catalyzed [4 + 2] annulation of α,β-unsaturated ketoximeacetates with 1,3-dicarbonyl compounds for the synthesis of three classes of structurally diverse pyridines has been developed. This method employs 1,3-dicarbonyl compounds as C2 synthons and enables the synthesis of multifunctionalized pyridines with diverse electron-withdrawing groups in moderate to good yields. The mechanistic investigation
Enantioselective Synthesis of Multifunctionalized 4<i>H</i>-Pyrans via Formal [4 + 2] Annulation Process by Bifunctional Phosphonium Salt Catalysis
作者:Jia-Hong Wu、Jianke Pan、Juan Du、Xiaoxia Wang、Xuemei Wang、Chunhui Jiang、Tianli Wang
DOI:10.1021/acs.orglett.9b04079
日期:2020.1.17
highly enantioselective formal [4 + 2] annulation involving electron-deficient allenes as C2-synthons has been developed under bifunctional phosphonium salt catalysis. With this catalytic protocol, a wide range of synthetically interesting and highly functionalized chiral 4H-pyran derivatives were readily prepared in good yields (up to 99%) with outstanding diastereo- and enantioselectivities (up to
Organocatalytic selenosulfonylation of the C–C doublebond of α,β-unsaturatedketones to construct two contiguous stereogenic centers in an aqueous medium was described. A series of α-selenyl and β-sulfonyl ketones with various functional groups were synthesized in good yields and enantioselectivities with saturated NaCl solution as the solvent. In addition, this protocol had been successfully scaled
The scope of the novel ruthenium‐catalyzed tandem cross‐metathesis/intramolecular‐hydroarylation sequence is described. This methodology offers a practical and efficient synthesis of structurally diverse and complex tetrahydrocarbazoles in good to excellent yields (up to 98 %). Moreover, preliminary efforts towards the development of an enantioselective version of the current process by sequential
Fe-Catalyzed Cycloisomerization of Aryl Allenyl Ketones: Access to 3-Arylidene-indan-1-ones
作者:Johannes Teske、Bernd Plietker
DOI:10.1021/acs.orglett.8b00612
日期:2018.4.20
A cycloisomerization of aryl allenylketones to 3-arylidene-indan-1-ones using a cationic Fe-complex as a catalyst is reported. The catalyst opens a synthetically interesting reaction pathway to this surprisingly underrepresented class of indanones that are not accessible using alternative catalytic systems.