AbstractA highly stereoselective organocatalytic α‐alkylation of 2‐arylacetaldehydes with a commercially available carbenium tetrafluoroborate is described. The stereoselective alkylation was carried out in acetonitrile/water, under air in the presence of a commercially available imidazolidinone (MacMillan’s catalyst). Key intermediates for the synthesis of bisabolanes were obtained through a simple chemistry. In particular a direct, enantioselective and facile synthesis of (R)‐(−)‐curcumene is described.magnified image
AbstractA highly stereoselective organocatalytic α‐alkylation of 2‐arylacetaldehydes with a commercially available carbenium tetrafluoroborate is described. The stereoselective alkylation was carried out in acetonitrile/water, under air in the presence of a commercially available imidazolidinone (MacMillan’s catalyst). Key intermediates for the synthesis of bisabolanes were obtained through a simple chemistry. In particular a direct, enantioselective and facile synthesis of (R)‐(−)‐curcumene is described.magnified image
On the Stereochemical Course of Palladium-Catalyzed Cross-Coupling of Allylic Silanolate Salts with Aromatic Bromides
作者:Scott E. Denmark、Nathan S. Werner
DOI:10.1021/ja910804u
日期:2010.3.17
palladium-catalyzed cross-couplingreactions of an enantioenriched, alpha-substituted, allylic silanolate salt with aromatic bromides has been investigated. The allylic silanolate salt was prepared in high geometrical (Z/E, 94:6) and high enantiomeric (94:6 er) purity by a copper-catalyzed S(N)2' reaction of a resolved allylic carbamate. Eight different aromatic bromides underwent cross-coupling with excellent
Enantioselective Synthesis of 4-Methyl-3,4-dihydroisocoumarin via Asymmetric Hydroformylation of Styrene Derivatives
作者:Bo Qu、Renchang Tan、Madison R. Herling、Nizar Haddad、Nelu Grinberg、Marisa C. Kozlowski、Xumu Zhang、Chris H. Senanayake
DOI:10.1021/acs.joc.8b02813
日期:2019.4.19
Enantioenriched aldehydes are produced through asymmetric hydroformylation of styrene derivatives using BIBOP-type ligands. The featured example is enantioselectivesynthesis of 4-methyl-3,4-dihydroisocoumarin, which was prepared in a 95.1:4.9 enantiomeric ratio from asymmetric hydroformylation of ethyl 2-vinylbenzoate followed by in situ lactonization during the reduction process. The conditions are