Stereoselective Syntheses of Tetrahydroesterastin‐β ‐Lactam Analogues

Huber, I.; Schneider, F

doi:10.1002/hlca.19940770420

Cited by 5 publications

(1 citation statement)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the advent of penicillin, the β-lactam antibiotics have been the subject of much discussion and investigation, within both the scientific and public sectors . More recently, β-lactam compounds have become attractive starting materials and intermediates in a wide range of synthetic settings and have demonstrated potential as inhibitors of various proteolytic enzyme systems . The primary biological targets of the β-lactam drugs are the penicillin binding proteins, a group of transpeptidases anchored within the bacterial cellular membrane which mediate the final step of cell wall biosynthesis.…”

Section: Introductionmentioning

confidence: 99%

Studies on Nonconventionally Fused Bicyclic β-Lactams

et al. 1998

View full text Add to dashboard Cite

Studies on Nonconventionally Fused Bicyclic β-Lactams.-A number of structurally novel [3.2.0]bicyclic β-lactam ring systems such as (IV), (IX), and (XIV) that have the lactam functionality arranged in alternative orientations within the four-membered ring are prepared. Semiempirical calculations indicate that the thermodynamic stabilities of the alternative isomeric ring systems are similar to that of the classical structure. The derivatives (Xb) and (XVI) show weak activity against Staphylococcus aureus or Vibrio cholerae.

show abstract

Section: Introductionmentioning

confidence: 99%

Studies on Nonconventionally Fused Bicyclic β-Lactams

et al. 1998

View full text Add to dashboard Cite

show abstract

Asymmetric Aldol Reactions Using Boron Enolates

1997

View full text Add to dashboard Cite

The directed aldol reaction allows the construction of new carbon–carbon bonds in a regio‐, diastereo‐, and enantioselective manner. The kinetically controlled, boron‐mediated aldol reaction is particularly powerful for the efficient synthesis of β‐hydroxy carbonyl compounds. Compared to other metal enolates, the boron–oxygen bond in boron enolates is relatively short which, on addition to aldehydes, leads to tight cyclic transition states and highly stereoselective carbon–carbon bond formation. Moreover, variation of the steric demands of the ligands on boron allows discrimination between competing transition states. Chiral auxiliaries attached to the boron enolate are frequently employed to control the relative and absolute stereochemistry of the aldol products. Asymmetric reactions using chiral ligands on boron are also possible and these produce useful enantiomerically enriched adducts. The utility of boron‐mediated aldol reactions has been demonstrated in numerous total syntheses of complex polyoxygenated natural products, and several of these are highlighted in the Application to Synthesis section of this chapter. Several reviews of the directed aldol reaction are available, including the Organic Reactions chapter by Mukaiyama in 1981. 9 The material covered in this review concerns only the asymmetric formation of β‐hydroxy carbonyl compounds using boron enolates and surveys the literature from 1981 until the end of 1995.

show abstract