A hemin/t-BuOOH-catalyzed oxidative phenol–enamine formal [3 + 2] cycloaddition has been developed, enabling the environmentally benign synthesis of valuable cyclopenta[b]benzofuran scaffolds under sustainable reaction conditions.
The first rearomatising (3 + 2) annulation of 3-nitroindoles and α,β-ynones has been achieved under metal-free conditions to access various α-arylidene cyclopenta[b]indoles.
The efficient and catalytic biscyclization of dithioallylic alcohols with 1-styrylnaphthols under mild conditions was achieved, thus affording pharmaceutically important cyclopenta[b]dihydronaphthofurans.
A substrate-controlled synthesis of cyclopenta[b]indoles has been developed from readily available 2,3-unfunctionalized indoles and acetone, under the catalysis of molecular iodine.
The first denitrative Pd(II)-catalyzed alkyne annulation reaction is reported for the synthesis of cyclopenta[b]chromanes.