Three-Component Ag-Catalyzed Enantioselective Vinylogous Mannich and Aza-Diels−Alder Reactions with Alkyl-Substituted Aldehydes
作者:Hiroki Mandai、Kyoko Mandai、Marc L. Snapper、Amir H. Hoveyda
DOI:10.1021/ja807243t
日期:2008.12.31
protocols for three-component catalytic enantioselectivevinylogousMannich (VM) reactions of alkyl-substituted aldimines (including those bearing heteroatom-containing substituents) and readily available siloxyfurans are presented. High efficiency and stereoselectivity is achieved through the use of o-thiomethyl-p-methoxyaniline-derived aldimines. Reactions, performed under an atmosphere of air and
Highly Diastereo- and Enantioselective Vinylogous Mannich Reactions of Fluorinated Aldimines with Siloxyfurans
作者:Qian-Yi Zhao、Zhi-Liang Yuan、Min Shi
DOI:10.1002/adsc.201000843
日期:2011.3.7
A highly regio‐ and enantioselective asymmetric vinylogousMannichreaction of readily available fluorinatedaldimines bearing a chiral auxiliary [(S)‐1‐phenylethyl group] with siloxyfurans to afford chiral fluorine‐containing γ‐butenolide or γ‐lactone derivatives has been developed in the presence of silver acetate (10 mol%) and axially chiral phosphine‐oxazoline ligand L1 (11 mol%). In most cases
yielding access to phosphonic γ‐(hydroxyalkyl)butenolides with excellent regio‐, diastereo‐ and enantiocontrol is reported. The simultaneous construction of up to two adjacent quaternary stereogenic centers by a catalytic asymmetric vinylogousMukaiyamaaldolreaction unites biologically and medicinally relevant entities, namely α‐hydroxy phosphonates and γ‐(hydroxyalkyl)butenolides. This is achieved by
A highly stereoselective vinylogousMukaiyamaMichael reaction (VMMR) leading to α‐keto phosphonate‐containing γ‐butenolides with two stereogenic centers is described. The presented transformation is catalyzed by a combination of a commercially available C2‐symmetric bisoxazoline (BOX) ligand and a copper salt and tolerates a variety of nucleophiles and electrophiles. The stereoselectivities of the
Iridium-Catalyzed Regioselective and Enantioselective Allylation of Trimethylsiloxyfuran
作者:Wenyong Chen、John F. Hartwig
DOI:10.1021/ja306850b
日期:2012.9.19
We report the regio- and enantioselectiveallylation of an ester enolate, trimethylsiloxyfuran. This enolate reacts at the 3-position with linear aromatic allylic carbonates or aliphatic allylic benzoates to form the branched substitution products in the presence of a metallacyclic iridiumcatalyst. This process provides access to synthetically important 3-substituted butenolides in enantioenriched