C–H Alkenylation of Indoles through a Dual 1,3-Sulfur Migration Process

Abstract

Methods for the modification of indole derivatives are powerful techniques in organic, medicinal, and biomolecular chemistry. Here, we report a protocol for the C–H alkenylation of N–H indoles with β-chlorovinyl dithianes to furnish alkenyl indoles through dual 1,3-sulfur rearrangements. This alkenylation protocol could selectively prepare a variety of vinyl indoles in moderate to high yields with excellent functional group tolerance.

Indium-catalyzed inter- and intramolecular dithianyl–alkyne metathesis reactions

“…11 Over the past few years, our group has also contributed to this field by developing a 1,3-sulfur rearrangement strategy of dithianes for the stereoselective synthesis of alkenyl products. [12][13][14] These transformations demonstrated the high potential of in situ generated thionium ions from 1,3-dithianes in carbon-carbon bond formation reactions (Scheme 1b). Based on these findings, we herein developed a novel metathesis reaction between 1,3-dithiane and alkyne, and the newly formed thionium ion from 1,3-dithiane could undergo [2+2] cycloaddition with alkyne either inter-or intramolecularly (Scheme 1c).…”

Synthesis of β,β-Dithioketones by Merging C–C and C–S Bond Cleavage in [1 + 1 + 1 + 1 + 1 + 1] Annulation

“…Owing to the special redox properties and outstanding reactivity of sulfur atoms, sulfur-containing compounds are widely used in the fields of medicine, pesticides, materials science, and organic chemistry . As an important sulfur-containing organic building block, 1,3-dithiane is typically used as a C1 unit or masked carbonyl equivalent , and has a wide range of applications in natural products construction and synthetic methodology . Besides, 1,3-dithiane derivatives reportedly exhibit insecticidal activity and good chemical stability .…”

Site-selective synthesis of indanyl-substituted indole derivatives via 1,3-dithiane induced Nazarov cyclization

“…27 In general, the vinyl thionium cation could undergo a variety of cationic cascades and subsequent rearrangement sequences with a suitable trapping agent. [27][28][29][30][31] Inspired by these works, we were curious whether the thionium ion originated from vinyl dithianes could undergo Nazarov-type cyclization/migration sequences. Herein, we report the first Nazarov-type reaction of vinyl 1,3-dithianes as precursors for the site selective synthesis of C2 and C3 indanyl-substituted indoles (Scheme 1d).…”