Synthesis of benzo-fused five- and six-membered heterocycles by palladium-catalyzed cyclocarbonylation

Synthesis of Functionalized Heterocycles via Oxidative Carbonylation

“…In 2011, Troisi and co-workers reported the synthesis of benzofused five-membered heterocycles via cyclocarbonylation of phenols, thiophenols, and anilines ortho-substituted by OH, SH, and NH groups in the presence of Et 3 N, 2 , and PPh 3 under CO pressure (Scheme 51b). For sulfonamides, o-hydroxybenzyl alcohol, and o-aminobenzyl alcohol, the corresponding six-membered heterocycles were obtained in moderate yields [141].…”

Oxidative Carbonylation as a Powerful Tool for the Direct Synthesis of Carbonylated Heterocycles

“…Synthesis of five-membered cyclic carbonates 62 by PdI 2 /KI-catalysed oxidative cyclocarbonylation of cyclic 1,2-diols 61. [57] Formation of molecular hydrogen accounted for the oxidative process (Scheme 43). Synthesis of glycerol carbonate (64) and α-d-glucofuranose 1,2:5,6-dicarbonate (66) by PdI 2 /KI-catalysed oxidative cyclocarbonylation of glycerol (63) and glucose (65), respectively.…”

“…[51a] The oxidative carbonylation of 1,2-and 1,3-diols to afford the corresponding cyclic carbonates in moderate to good yields has also recently been achieved through the use Scheme 42. [57] Scheme 43. [51a] of (neocuproine)Pd(OAc) 2 or Pd(OAc) 2 /(-)-sparteine as the catalytic system, in the presence of N-chlorosuccinimide or dichloroisocyanuric acid as the oxidant and under atmospheric pressure of CO. [52] A bimetallic system, based on Pd(OAc) 2 /Mn(acac) 3 , has also been employed for the oxidative carbonylation of some 1,2-diols, including glycerol, under 20 atm of a CO/O 2 /N 2 mixture at 60°C.…”

Organic Base-Catalyzed C–S Bond Construction from CO2: A New Route for the Synthesis of Benzothiazolones

“…The catalytic activity of DBN was greatly influenced by the nature of solvent. The product yield increased in the following order: dimethyl sulfoxide (DMSO) < CH 3 CN < N,N-dimethylformamide (DMF) < 1-methyl-2-pyrrolidinone (NMP) ( Table 1, entries 5,[10][11][12]. This corresponded with the order of CO 2 solubility in these solvents (expressed as Henry's constant), DMSO (12.67) > CH 3 CN (9.049) > DMF (7.966) > NMP (7.61) [41].…”

“…To date, numerous efforts focused on the development of improved methods for the synthesis of this heterocyclic compounds [6][7][8][9][10]. Among them, the direct cyclocarbonylation of 2-aminothiophenols in the presence of carbonylation agents, such as phosgene [11], CO [12], ClCO 2 Et [13], dimethyl carbonate [14], urea [15], and isocyanates [16] (Scheme 1a), is one of the most simple and versatile methods. However, phosgene is highly toxic and corrosive, the reactions involving CO are generally catalyzed by transition metals, and the use of super-stoichiometric amounts of carbonyl sources are all incompatible with green-chemistry principles.…”