Enantioselective synthesis of saddle-shaped eight-membered lactones with inherent chirality via organocatalytic high-order annulation.

Shi, Shao-Qing; Cui, Chen-Chang; Xu, Lin-Lin; Zhang, Jin-Peng; Hao, Wen-Juan; Wang, Jianyi; Jiang, Bo

Inherently chiral medium-ring derivatives have important applications in many research fields, such as materials science, molecular recognition, and asymmetric catalysis. However, the enantioselective assembly of these molecules, especially by organocatalytic strategies, remains a formidable challenge, and few methods are available. Here, we report the enantioselective NHC-catalyzed (NHC: N-heterocyclic carbenes) formal high-order (5 3) annulation of 1-(2-indolyl)naphthalen-2-ols with ynals. In the presence of an NHC pre-catalyst, base, Lewis acid and oxidant, this protocol enables the catalytic formation of C–C and C-O bonds, providing practical and facile access to an array of inherently chiral saddle-shaped eight-membered lactones featuring an oxocin-2-one scaffold with structural diversity in good efficiency and excellent enantiocontrol. Moreover, the scale-up preparation and representative late-stage transformations of the eight-membered lactones further demonstrate the application potential of this synthetic technology. Inherently chiral medium-ring derivatives have important applications in many research fields, but few enantioselective methods are available. Herein, the authors report the enantioselective N-heterocyclic carbenes-catalyzed formal (5 3) annulation of 1-(2-indolyl)naphthalen-2-ols with ynals for the synthesis of eight-membered lactones.

MATERIALS science; LEWIS acids; LACTONES; CARBENES; CHIRALITY; ANNULATION; MOLECULAR recognition

Nature Communications, 2024, Vol 15, Issue 1, p1

2041-1723

Academic Journal

10.1038/s41467-024-52823-3