One-Pot Synthesis of Less Accessible <i>N</i>-Boc-Propargylic Amines through BF<sub>3</sub>-Catalyzed Alkynylation and Allylation Using Boronic Esters
作者:Kento Yasumoto、Taichi Kano、Keiji Maruoka
DOI:10.1021/acs.orglett.9b00931
日期:2019.5.3
amines is described via an alkynylation or allylation of alkynyl-substituted N-Boc-imines. Our strategy relies on the BF3-mediated in situgeneration of alkynyl imines followed by alkynylation or allylation with the corresponding boronic esters. A range of lessaccessible N-Boc-propargylic amines were obtained in moderate to good yields under mild and acidic conditions with higher atom economy compared
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.
organocatalytic reaction between propargyl alcohols and trialkenylboroxines. Our strategy relies on acid‐mediated generation of the carbocationic intermediate from propargyl alcohols followed by enantioselective alkenylation with trialkenylboroxines. A range of chiral 1,4‐enynes were obtained in moderate to good yields with high levels of enantioselectivity. Use of a highly acidic chiral N‐triflyl phosphoramide
Asymmetric Petasis Reactions Catalyzed by Chiral Biphenols
作者:Sha Lou、Scott E. Schaus
DOI:10.1021/ja8018934
日期:2008.6.1
Chiralbiphenolscatalyze the enantioselective Petasis reaction of alkenyl boronates, secondary amines, and ethyl glyoxylate. The reaction requires the use of 15 mol % of (S)-VAPOL as the catalyst, alkenyl boronates as nucleophiles, ethyl glyoxylate as the aldehyde component, and 3 A molecular sieves as an additive. The chiral alpha-amino ester products are obtained in good yields (71-92%) and high