Synthesis of cis-5,5a,6,10b-Tetrahydroindeno[2,1-b]indoles through Palladium-Catalyzed Decarboxylative Coupling of Vinyl Benzoxazinanones with Arynes

Abstract

A novel palladium-catalyzed decarboxylative coupling reaction of vinyl benzoxazinanones with arynes which may feature an intramolecular nucleophilic attack of an amino group at the central carbon of π-allylpalladium intermediate has been developed. The cis-5,5a,6,10b-tetrahydroindeno[2,1-b]indoles were generated in moderate to good yields. One key to the success of the present reaction was to achieve comparable rates for the palladium-catalyzed decarboxylation and aryne formation steps.

An Update of Transition Metal-Catalyzed Decarboxylative Transformations of Cyclic Carbonates and Carbamates

“…In allylic chemistry, the nucleophilic attack of π-allyl palladium intermediate generally occurred at the terminal or internal carbon. However, this conversion features an intramolecular nucleophilic attack of the amide group at the central carbon of the π-allyl palladium intermediate, though a deeper understanding of the mechanism is still required [17]. The Shibata group reported an unprecedented intermolecular cyclization of cyclic carbamate and sulfur ylides toward the formation of 4-trifluoromethyl-dihyroquinolines (Scheme 3b, path a); without externally added acceptors, a cyclization process would also be possible through an intramolecular attack of the zwitterionic π-allyl intermediate (Scheme 3b, path b) [18].…”

Recent Progress in the Transition Metal Catalyzed Synthesis of Indoles

“…During the drafting of this review many papers continued to appearing in the literature. They have been not discussed here but they could be of interest for the reader [147][148][149][150][151][152][153][154][155][156][157][158][159]. Recently, the classical syntheses, which are still widely used and improved, have been juxtaposed with many transition metal catalyzed syntheses.…”

Advances in Palladium‐Catalyzed Decarboxylative Cycloadditions of Cyclic Carbonates, Carbamates and Lactones

“…reported a novel DCs of 4‐vinyl benzoxazinanones 108 with arynes 140 generated in situ from o ‐(trimethylsilyl)aryl triflate 139 (Scheme 69). [51] At first, a decarboxylation of 108 with palladium catalysis provided π‐allyl palladium species 3.2A . Then, an intramolecular nucleophilic attack of nitrogen anion to the central carbon of π ‐allyl palladium unit gave the palladacyclobutane intermediate 3.2U .…”