Radical cyclization of alkynyl aryl ketones for the synthesis of 3-seleno-substituted thiochromones and chromones

Abstract

Herein we present an alternative and transition-metal-free procedure to access 3-organoselanylthiochromones and 3-organoselanylchromones from the cyclization reaction between alkynyl aryl ketones and diorganyl diselenides promoted by Oxone®.

Electrochemical Selenylation of Alkynyl Aryl Ketones: Efficient Synthesis of 3‐Selenylated Chromones under Catalyst‐ and Chemical‐Oxidant‐Free Conditions

“…Experimental procedures and spectra data of each products are provided in the online Supporting Information. Additional references were cited within the Supporting Information [9–18] …”

“…Additional references were cited within the Supporting Information. [9][10][11][12][13][14][15][16][17][18]…”

“…To date, the research on developing the synthetic methodology for such moieties is well-established (Scheme 1). [9][10][11][12][13] However, most of them run in harsh conditions and suffer from some shortcomings, for instance, the requirement of high loading amount of transition-metal salt, excess strong oxidant, high temperature, and low efficiency. These drawbacks are usually unavoidable and decrease the practicability of these kinds of methods.…”

Ag(i)-catalyzed three-component radical cascade synthesis of 3-organoselenyl chromones from 2-methoxyaryl alkynones, Se powder and organic boronic acids

“…According to the starting materials and the reported reaction mechanism, these methods can be classified into three catalogues. The first one is the electrophilic cascade cyclization of 2-methoxyaryl alkyones with organoselenium cations, which were in situ generated via oxidation of RSeSeR with various chemical oxidants, such as FeCl 3 , 4 PIFA, 5 Oxone 6 or Selectfluor. 7 Not long ago, the electrooxidation method was also explored by the Ruan group for the preparation of 3-organoselenyl chromones via this approach 8 (Scheme 1a).…”

Molybdenum(v)-mediated switching of the C(sp2)–Se bond of phenylselenyl-functionalized arenes or heterocycles under mild conditions

“…3 On the one hand, phenylselenyl-substituted arenes and heterocycles are easily obtained by phenylselenyl-functionalization of C(sp 2 )–H bond 4 and C(sp 2 )–halogen bond 5 on aromatic and heterocyclic rings (Scheme 1, a ) and by cyclization/phenylselenylization of alkynes or enamines (Scheme 1, b ). 6 On the other hand, phenylselenyl-substituted arenes and heterocycles can be oxidized to form selenoxides 7 a or high-valent selenium salts 7 b (Scheme 1, e and f ), or undergo lithiation/deselenylization reaction and subsequent treatment with protons 7 c or electrophiles 7 d to yield a hydrogenated- or E + -functionalized products (Scheme 1, c ). Gilson Zeni achieved the palladium-catalyzed Suzuki cross-coupling of 3-phenylselenyl spiro[4,5]trienones with phenylboronic acids in 30% to 70% yields 8 a while Silveira developed a Fe(acac) 3 -catalyzed cross-coupling reaction between vinylic selenides and Grignard reagents, providing the alkenes in good to excellent yields 8 b (Scheme 1, d ).…”