Synthesis of Phosphonylated and Thiolated Indenones by Manganese(III)‐Mediated Addition of Phosphorus‐ and Sulfur‐Centered Radicals to 1,3‐Diarylpropynones

Abstract

Phosphorus‐ or sulfur‐centered radicals generated from the reaction of manganese(III) acetate with dialkyl phosphonates or arylthiols undergo selective additions to conjugated alkynes followed by cyclization and rearomatization to afford 2‐phosphonyl‐ or 2‐thioaryl‐substituted indenones in fair to good yields.

An Approach to Benzophosphole Oxides through Silver‐ or Manganese‐Mediated Dehydrogenative Annulation Involving CC and CP Bond Formation

“…Consequently, we investigated the annulation reaction in detail to provide an unprecedented direct route to benzophosphole derivatives. Furthermore, it was found that these radical processes can also be promoted by a Mn III salt10a, 11 as well as Ag I .…”

“…It has been reported that P‐centered radicals can be formed in the presence of Mn(OAc) 3 through homolytic PH bond cleavage 10a. Therefore, we employed Mn(OAc) 3 ⋅2 H 2 O (1 mmol) in the place of AgOAc for the reaction of 1 a with 2 a , and 3 aa was formed in 50 % yield (entry 9 in Table 1).…”

Phosphorylation of C–H bonds of aromatic compounds using metals and metal complexes

“…149 They also react with 1,3-diarylpropynones affording phosphonated indenones. 150 The authors also found that phosphinoyl radical [e.g. Ph 2 (O)P . ]…”

Tetraalkynylstannanes in Synthesis of α,β-Acetylenic Ketones

“…α,β-Acetylenic ketones are widely used in organic synthesis as starting reagents for the preparation of indenones [1], benzodiazepines [2], chromones [3], frutinones [4], pyrazoles [5], and phosphonylated indenones [6]. Such ketones can be prepared by Sonogashira coupling of terminal alkynes and acyl halides.…”