The first successful example of the direct synthesis of Weinreb amides using catalytic hydroxy-directed dehydrative amidation of carboxylicacids using the diboronic acid anhydride catalyst is described. The methodology is applicable to the concise syntheses of eight α-hydroxyketone natural products, namely, sattabacin, 4-hydroxy sattabacin, kurasoins A and B, soraphinols A and B, and circumcins B
Rhodium Carbenoid Initiated O–H Insertion/Aldol/Oxy-Cope Cascade for the Stereoselective Synthesis of Functionalized Oxacycles
作者:Kiran Chinthapally、Nicholas P. Massaro、Indrajeet Sharma
DOI:10.1021/acs.orglett.6b03229
日期:2016.12.16
A novel diazo-cascade approach has been developed for the synthesis of nine-membered oxacycles utilizing readily accessible β-hydroxy vinyl ketones and vinyl diazo esters. The Rh(II)-catalyzed cascade reaction begins with carbene O–H insertion followed by an intramolecular aldol cyclization to provide a substituted tetrahydrofuran intermediate that undergoes an oxy-Cope rearrangement to provide functionalized
作者:Dimitri Hirsch-Weil、Khalil A. Abboud、Sukwon Hong
DOI:10.1039/c0cc02211j
日期:——
C
1-symmetric isoquinoline-based chiral diaminocarbene ligands (MIQ) have been developed to block three quadrants of the metal coordination sphere, complementing C2-symmetric biisoquinoline-based ligands (BIQ). MIQ-Cu complexes catalyzed conjugate borylation of various α,β-unsaturated amides in good yields (82–99%) and enantioselectivities (75–87% ee).