Domino Reaction of 2,4-Diyn-1-ols with 1,3-Dicarbonyl Compounds: Direct Access to Aryl/Heteroaryl-Fused Benzofurans and Indoles

International audienceA domino propargylation/furanylation (intramolecular exo-dig-cyclization)/benzannulation reaction of 2,4-diyn-1-ols with 1,3-dicarbonyl compounds has been developed for the first time. This provides a novel and effective method for the preparation of aryl/heteroaryl-fused benzofurans from easily accessible starting materials in a single step. The methodology was extended to pyrrolyl-benzannulation to obtain aryl/heteroaryl-fused indoles. Further, application of this approach in the synthesis of eustifoline D and dictyodendrin structural frameworks has been demonstrated

One-Pot Consecutive Sulfonamidation/<i>ipso</i>-Cyclization Strategy for the Construction of Azaspirocyclohexadienones

Harnessing of Morita–Baylis–Hillman (MBH) carbonates of acetylenic aldehydes as handy synthons has allowed a facile synthesis of azaspirocyclohexadienones by sequential DABCO-promoted sulfonamidation/ICl-mediated <i>ipso</i>-iodocyclization reactions. A variety of MBH-carbonates having aryl or heteroaryl groups on the alkyne functionality fruitfully participated in the one-pot <i>ipso</i>-annulation reaction to provide the corresponding 3-iodo spirocyclohexadienones. The sulphonamide functionality was further utilized to construct the tricyclic fused-sultam framework