A palladium iodide catalyzed regioselective carbonylative route to isocoumarin and thienopyranone carboxylic esters

Transition-Metal-Catalyzed Carbonylative Multifunctionalization of Alkynes

“…Furthermore, this intramolecular anti -5- exo - dig alkoxycarbonylation has been successfully extended to the synthesis of oxazolidin-2-ones and bisoxazolines from propynyl amines and acetylenic diamides, respectively. Very recently, a 6- endo - dig cyclization–alkoxycarbonylation of 2-alkynylbenzoic acid under a PdI 2 /KI-catalytic system was established by the same group . Using oxygen as an external oxidant and alcohol as the nucleophile, a wide range of isocoumarin-4-carboxylic esters were constructed in good yields.…”

“…Very recently, a 6-endo-dig cyclization−alkoxycarbonylation of 2-alkynylbenzoic acid under a PdI 2 /KI-catalytic system was established by the same group. 107 Using oxygen as an external oxidant and alcohol as the nucleophile, a wide range of isocoumarin-4-carboxylic esters were constructed in good yields. Interestingly, when R 1 was a trimethylsilyl (TMS) group, 108 the reaction underwent a syn-5-exo-dig cyclization to afford alkyl (Z)-2-[3-oxoisobenzofuran-1-(3H)-ylidene]acetates as the major products.…”

Straightforward Synthesis of Bis[(trifluoromethyl)sulfonyl]ethylated Isocoumarins from 2-Ethynylbenzoates

“…The 3,4-disubstituted isocoumarin framework displays interesting biological properties and it is widely spread in natural products and drugs (Scheme , top). , Consequently, the preparation of this privileged core has been extensively documented . Notable synthesis of isocoumarins include the palladium-catalyzed oxidative alkoxycarbonylation of 2-alkynylbenzoic acids (Scheme a), the rhodium-catalyzed coupling of benzoic acids with α-diazocarbonyls (Scheme b), and the palladium-catalyzed cyclization of 2-iodobenzoic acids with ynamides (Scheme c) . Despite the merits of previously reported procedures, most of them require the use of transition metals, hazardous reagents, or harsh reaction conditions.…”

Disclosing Polycyclic Heterocycles: Synthesis of Furothienopyran and Pyranothienopyran Derivatives by Palladium Iodide Catalyzed Carbonylative Double Cyclization

“…In this work, we report on the application of our PdI 2 /KI‐catalyzed oxidative carbonylation methodology [11,12] to the direct synthesis of furothienopyrandiones 2 , 4 and pyranothienopyrandiones 6 , 8 by carbonylative double cyclization of readily available thiophenecarboxylic acids bearing an ω‐hydroxyalkynyl substituent in vicinal position ( 1 , 3 , 5 , 7 ), as shown in Scheme 1. Our approach thus opens to way to previously unknown classes of functionalized polycyclic heterocycles with potential important applications [13,14] in one synthetic catalytic step and starting from very simple building blocks (thiophenecarboxylic acid derivatives and CO).…”

“…In this context, we have recently reported several examples, which have allowed the direct synthesis of 6,6a-dihydrothieno [3,2-b]furan-2(5H)-one, [5] 3,4-dihydropyrrolo [3,4-b]indol-1(2H)one, [6] furo [3,4-b]benzofuran-1(3H)-one, [7] furo [3,4b]indol-1-one, [8] and 6,6a-dihydrofuro [3,2-b]furan-2(5H)-one [9] derivatives, using the simple catalytic system PdI 2 /KI (introduced by our research group as oxidative carbonylation catalyst at the beginning of the 1990ies). [10] In this work, we report on the application of our PdI 2 /KI-catalyzed oxidative carbonylation methodology [11,12] to the direct synthesis of furothienopyrandiones 2, 4 and pyranothienopyrandiones 6, 8 by carbonylative double cyclization of readily available thiophenecarboxylic acids bearing an ω-hydroxyalkyn-yl substituent in vicinal position (1,3,5,7), as shown in Scheme 1. Our approach thus opens to way to previously unknown classes of functionalized polycyclic heterocycles with potential important applications [13,14] in one synthetic catalytic step and starting from very simple building blocks (thiophenecarboxylic acid derivatives and CO).…”