Thermal [2 + 2]‐Cycloadditions of Tetracyanoethylene to Cyclic Thioenol Ethers

Fries, Siegfried; Gollnick, Klaus

doi:10.1002/anie.198008311

Cited by 13 publications

(1 citation statement)

References 4 publications

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“…In further support of a stepwise process, cycloisomerization of 46 was conducted in the presence of tetracyanoethylene (TCNE) to afford dihydrofuran 54 (Scheme 10). This result is consistent with the ability of dihydrofurans to undergo formal [2+2] cycloaddition with suitable electrophiles such as TCNE 44 and dimethyl acetylenedicarboxylate (DMAD) 45 through proposed zwitterionic intermediates similar to 55.…”

Section: 3940supporting

confidence: 81%

Gold(I)-Mediated Cycloisomerization/Cycloaddition Enables Bioinspired Syntheses of Neonectrolides B–E and Analogues

et al. 2019

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Development of a synthetic route to the oxaphenalenone (OP) natural products neonectrolides BE is described. The synthesis relies on gold-catalyzed 6-endo-dig hydroarylation of an unusual enynol substrate as well as a one-pot Rieche formylation/cyclization/deprotection sequence to efficiently construct the tricyclic oxaphenalenone framework in the form of a masked orthoquinone methide (o-QM). A tandem cycloisomerization/[4+2] cycloaddition strategy was employed to quickly construct molecules resembling the neonectrolides. The tricyclic OP natural product SF226 could be converted to corymbiferan lactone E and a related masked o-QM. Our study culminates with the application of the tandem reaction sequence to syntheses of neonectrolides BE as well as previously unreported exo-diastereomers.

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Section: 3940supporting

confidence: 81%