The protease-catalyzed synthesis of amino acid est-carbohydrate conjugates as glycopeptide analogues has been achieved in a highly regioselective and carbohydrate-specific manner using amino acid vinyl ester acyl donors and minimally or completely unprotected carbohydrate acyl acceptors, which together probed active sites of proteases to reveal yield efficiencies that are modulated by the carbo...

The fused 2-vinyl or 2-phenyl substituted cyclobutanones 4 undergo stereoselective ring openings by the action of alkoxide ions (t-BuO(-) or MeO(-)) to produce novel vicinally disubstituted cycloalkene derivatives 5 and 6 in moderate to high yields. The ring cleavage usually occurs with complete regioselectivity. The accessibility of γ,δ-unsaturated ester or acid derivatives makes this transfor...

The first total syntheses of schilancidilactones A and B, schilancitrilactone A, and 20-epi-schilancitrilactone A have been accomplished using a nickel-catalyzed cross coupling of alkyl bromide with vinyl stannane as the final step. The other key steps include late-stage C(sp)–H bromination, the oxidative cleavage of a diol to provide the requisite ketone and ester for schilancidilactones A and...

Merging is the game! The coupling of a domino reaction and an internal neutral redox reaction constitutes an excellent manifold for the stereoselective synthesis of di- and trisubstituted olefins featuring a malonate unit, an ester, or a free carboxylic acid as substituents at the allylic position (see scheme; MW=microwave). The reaction utilizes simple starting materials (propargyl vinyl ether...

The first total syntheses of schilancidilactones A and B, schilancitrilactone A, and 20-epi-schilancitrilactone A have been accomplished using a nickel-catalyzed cross coupling of alkyl bromide with vinyl stannane as the final step. The other key steps include late-stage C(sp3)-H bromination, the oxidative cleavage of a diol to provide the requisite ketone and ester for schilancidilactones A an...

Tertiary propargyl vinyl ethers armed with an electron-withdrawing group (amide or ester) at the tertiary propargylic position have been efficiently transformed into trisubstituted C(2)-chain functionalized furans. The metal-free domino transformation involves a microwave-assisted tandem [3,3]-propargyl Claisen rearrangement/5-exo-dig O-cyclization reaction. The manifold can be performed in a o...

BACKGROUND Metal-working fluids contain complex mixtures of chemicals and metal workers constitute a potential risk group for the development of allergic contact dermatitis. CASE PRESENTATION Two metal workers developed allergic contact dermatitis on the hands and lower arms from exposure to a neat oil used in metal processing. Patch testing revealed that the relevant contact allergen was a c...

Abstract Crosslinking thermosets with hyperbranched polymers confers them superior comprehensive performance. However, it still remains a further understanding of polymer crosslinking from the molecular chains to role aggregates. In this study, three polysiloxane structures (HBPSi‐R) are synthesized as model macromolecules, each featuring distinct terminal groups (R denotes amino, epoxy, and vi...

Presented here is a full account on the development of a strategy culminating in the first total synthesis of the architecturally complex daphniphyllum alkaloid, (-)-calyciphylline N. Highlights of the approach include a highly diastereoselective, intramolecular Diels-Alder reaction of a silicon-tethered acrylate; an efficient Stille carbonylation of a sterically encumbered vinyl triflate; a on...