Enantioselective Boronate Additions to N-Acyl Quinoliniums Catalyzed by Tartaric Acid
摘要:
Tartaric acid catalyzes the asymmetric addition of vinylboronates to N-acyl quinoliniums, affording highly enantioenriched dihydroquinolines. The catalyst serves to activate the boronate through a ligand-exchange reaction and generates the N-acyl quinolinium in situ from the stable quinoline-derived N,O-acetal.
vinylboronates and α‐iminoamides are effectively catalyzed by the novel hydroxy–thiourea catalyst 1 (up to 86 % yield, 93 % ee; see scheme). This reaction can be applied not only to the synthesis of the unnatural amino acid monomers but also to peptide oligomers.
Enantioselective Addition of Boronates to Chromene Acetals Catalyzed by a Chiral Brønsted Acid/Lewis Acid System
作者:Philip N. Moquist、Tomohiro Kodama、Scott E. Schaus
DOI:10.1002/anie.201003469
日期:2010.9.17
Chiral α,β‐dihydroxy carboxylic acids catalyze the enantioselectiveaddition of alkenyl and aryl boronates to chromene acetals. The optimal carboxylic acid is the easily available tartaric acid amide shown in the scheme. Spectroscopic and kinetic mechanistic studies demonstrate that an exchange process generates a reactive dioxoborolane intermediate leading to enantioselectiveaddition to the pyrylium
Enantioselective Multicomponent Condensation Reactions of Phenols, Aldehydes, and Boronates Catalyzed by Chiral Biphenols
作者:Keith S. Barbato、Yi Luan、Daniele Ramella、James S. Panek、Scott E. Schaus
DOI:10.1021/acs.orglett.5b02954
日期:2015.12.4
Chiral diols and biphenolscatalyze the multicomponent condensation reaction of phenols, aldehydes, and alkenyl or aryl boronates. The condensation products are formed in good yields and enantioselectivities. The reaction proceeds via an initial Friedel–Crafts alkylation of the aldehyde and phenol to yield an ortho-quinone methide that undergoes an enantioselectiveboronateaddition. A cyclization
作者:Giovanni Muncipinto、Philip N. Moquist、Stuart L. Schreiber、Scott E. Schaus
DOI:10.1002/anie.201103271
日期:2011.8.22
Multicomponent Petasisreactions: The first diastereoselectivePetasisreaction catalyzed by chiral biphenols that enables the synthesis of syn and anti β‐amino alcohols in pure form has been developed. The reaction exploits a multicomponent approach that involves boronates, α‐hydroxy aldehydes, and amines (see scheme).