Intramolecular transamidation of β-lactams as a means for the enzymatic control of ring opening: Effect of substituents on the rate of reaction
作者:Luca Banfi、Giuseppe Guanti、Marcello Rasparini
DOI:10.1016/s0040-4039(98)02118-2
日期:1998.12
A series of simple monocyclic β-lactams bearing side-chains, containing amino groups, have been synthesized, and the rate of their intramolecular transamidation studied. Protection of the amino group with an enzymatically cleavable group, allows us to selectively control the ring enlargement process.
Selective reduction of alkynes to cis-alkenes by hydrometallation using [(Ph3P)CuH]6.
作者:John F. Daeuble、Colleen McGettigan、Jeffrey M. Stryker
DOI:10.1016/s0040-4039(00)97371-4
日期:1990.1
Selective reduction of alkynes to the corresponding alkenes is reported using the stable, readily prepared copper(I) hydride reagent, [(Ph3P)CuH]6. Terminal alkynes are reduced at room temperature, unactivated internal alkynes react only at elevated temperature. Disubstituted alkynes with propargyl activation are also reduced, giving cis-olefins selectively. Protection of propargylic alcohol functionality
Synthesis of Trisaccharides by Hetero-Diels-Alder Welding of Two Monosaccharide Units
作者:Jatta A. Himanen、Petri M. Pihko
DOI:10.1002/ejoc.201200277
日期:2012.7
selectivities in the HDA reaction were obtained by using chiral Schiff base chromium complexes. Disaccharide products were accessible by reaction of Danishefsky's diene with acetyl- and benzyl-protected galactoside aldehydes. For the synthesis of trisaccharide products, acetyl-protected glucose or galactose-derived dienes were fused with monosaccharide-derived aldehydes using chromium catalysts for the
Intramolecular Opening of β-Lactams with Amines as a Strategy Toward Enzymatically or Photochemically Triggered Activation of Lactenediyne Prodrugs
作者:Luca Banfi、Giuseppe Guanti、Marcello Rasparini
DOI:10.1002/ejoc.200390188
日期:2003.3
to develop a general strategy for selective activation of designed enediyne prodrugs belonging to the “lactenediyne” family, we studied the scope of intramolecular transamidation of simple monocyclic β-lactams bearing a tethered amine. The effect of substituents, of reaction media, and of the type of tether, on the rate of transamidation is disclosed. The possibility of triggering the transamidation
An efficient preparation of γ‐lactols and methylene‐γ‐lactols is described. Highly acid‐sensitive lactols are prepared in a concise manner by using a radicalcyclization of aluminumacetals. The precursors for the radical reactions are readily prepared from allyl or propargyl alcohols and α‐bromo acids. Functionalization of the resulting γ‐lactols and methylene‐γ‐lactols can be achieved following isolation