Formation of Nine-Membered Lactams by Oxidative Ring Expansion of 4-Hydroxyhydroindoles: A Biomimetic Approach toward the Tuberostemonone Ring System?

Formation of Nine-Membered Lactams by Oxidative Ring Expansion of 4-Hydroxyhydroindoles:  A Biomimetic Approach toward the Tuberostemonone Ring System

Synthesis and Ag(I) Complexation Studies of Tethered Westiellamide

A new tethered macrocyclic ring system based on the natural product westiellamide was prepared to increase the affinity and ease of complexation to Ag(I) ions. NMR and fluorescence Ag(I) titrations confirmed that the tethered macrocycles preserve the unique, high-affinity coordination mode of westiellamide

Synthesis of the 3-Aza-[7]-paracyclophane Core of Haouamine A and B

The synthesis of the highly strained 3-aza-[7]-paracyclophane core of haouamines A and B is based on a macrocyclization−aromatization protocol, allowing for a stepwise increase in ring strain and establishing the oxygenation pattern of the natural products

Zirconocene−Zinc Transmetalation and in Situ Catalytic Asymmetric Addition to Aldehydes

Zirconocene−Zinc Transmetalation and in Situ Catalytic Asymmetric Addition to Aldehyde

A New Ligand Scaffold for Catalytic Asymmetric Alkylzinc Additions to Aldehydes

1,3-Azole derivatives of 2-aminocyclohexanecarboxylic acid represent a new class of bidentate ligands for metal-mediated catalytic asymmetric synthesis. N-[2-(4-Isopropyl-4,5-dihydrooxazol-2-yl)cyclohexyl]methanesulfonamide (6) is particularly well suited for the addition of alkylzinc reagents to aliphatic aldehydes in high enantiomeric excess

Water-Accelerated Tandem Claisen Rearrangement−Catalytic Asymmetric Carboalumination

The addition of stoichiometric quantities of water accelerates both the trimethylaluminum-mediated aromatic Claisen reaction and the chiral zirconocene-catalyzed asymmetric carboalumination of terminal alkenes. The two reactions occur in a tandem sequence resulting in the selective formation of two new C−C and one C−O bond after oxidative quench of the intermediate trialkylalane

Convergent Approach to (<i>E</i>)-Alkene and Cyclopropane Peptide Isosteres

Trisubstituted (E)-alkene isosteres (TEADIs) and novel cyclopropane amide bond isosteres (CPDIs) were synthesized by aldimine addition and three-component aldimine addition−cyclopropanation methodologies, respectively. These new peptide mimetics can serve as β-turn promoters

Convergent Approach to (<i>E</i>)-Alkene and Cyclopropane Peptide Isosteres

Trisubstituted (E)-alkene isosteres (TEADIs) and novel cyclopropane amide bond isosteres (CPDIs) were synthesized by aldimine addition and three-component aldimine addition−cyclopropanation methodologies, respectively. These new peptide mimetics can serve as β-turn promoters

Total Synthesis and Revision of Stereochemistry of the Marine Metabolite Trunkamide A

The isolation of the cytotoxic Lissoclinum sp. metabolite trunkamide A was reported in 1996. After completion of a total synthesis in 1999, it became clear that the structure of this marine natural product had to be revised. We now report the first preparation of actual trunkamide A in a total synthesis that serves as an unambiguous structural and stereochemical proof. Highlights of our synthetic strategy are a Lewis acid assisted aziridine opening that was used for the preparation of the novel reverse-prenylated serine and threonine side chains as well as an efficient oxazoline−thiazoline interconversion on the macrocyclic skeleton. In addition, several stereoisomers prepared by complementary synthetic protocols serve to illustrate the general scope of our methodology and confirm the configurational assignment

Formation of Nine-Membered Lactams by Oxidative Ring Expansion of 4-Hydroxyhydroindoles: A Biomimetic Approach toward the Tuberostemonone Ring System?

Formation of Nine-Membered Lactams by Oxidative Ring Expansion of 4-Hydroxyhydroindoles:  A Biomimetic Approach toward the Tuberostemonone Ring System