Rapid, two-pot procedure for the synthesis of dihydropyridinones; total synthesis of aza-goniothalamin

• Thomas J. Cogswell,
• Craig S. Donald and
• Rodolfo Marquez

Beilstein J. Org. Chem. 2020, 16, 135–139, doi:10.3762/bjoc.16.15

• produce the target dihydropyridinones efficiently and in high yields. Keywords: amidoallylation; aza-goniothalamin; dihydropyridinones; protecting-group-free; ring-closing metathesis; two-pot procedure; Introduction Six-membered nitrogen heterocycles are prevalent in many naturally occurring and

• conditions [27][28]. Ring-closing metathesis of diene 10 then proceeded in good yield (68%) to complete a fast and efficient, protecting-group-free, two-pot procedure for the racemic synthesis of aza-goniothalamin 1. Conclusion In summary, a two-pot, protecting-group-free procedure for the synthesis of

Assembly of fully substituted triazolochromenes via a novel multicomponent reaction or mechanochemical synthesis

• Robby Vroemans,
• Yenthel Verhaegen,
• My Tran Thi Dieu and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2689–2697, doi:10.3762/bjoc.14.246

• -nitrochromenes. Because our first step is best performed solvent-free, we opted to try our own optimized solvent-free conditions for the in situ syntheses of 3-nitro-2H-chromenes, followed by the 1,3-dipolar cycloaddition in a reaction vial. Despite being a two-pot procedure, purification of the intermediate 3

End game strategies towards the total synthesis of vibsanin E, 3-hydroxyvibsanin E, furanovibsanin A, and 3-O-methylfuranovibsanin A

• Brett D. Schwartz,
• Craig M. Williams and
• Paul V. Bernhardt

Beilstein J. Org. Chem. 2008, 4, No. 34, doi:10.3762/bjoc.4.34

• cleavage. Nevertheless, the acetone sidechain could be introduced in ~20% overall yield allowing end game functionalisation (as discussed below). α-Hydroxylation was next investigated. Considering the observed preference for regiospecific enolate formation in our system we devised a simple two pot

• procedure based on the epoxidation of silyl enol ethers. Ketone 23 was smoothly converted into the TBS enol ether 27 (85% yield) with TBS triflate, which was then treated with dimethyldioxirane (DMDO). When work up was restricted to a simple 1 M hydrochloric acid wash (i.e. separatory funnel) only the