Abstract:2-(Arylmethylene)tetralin-1-thione and 1-aryl-3-phenyl-2-propene-1-thione (thiochalcone) reacted with diphenylcydopropenone across the =C–CO bond giving a thiophene derivative and a polysubstituted phenol with the arylketene/sulfur elimination, whereas the reaction with diphenylcydopropenethione took place at the C=S bond affording a spiro compound.
“…Diphenylcyclopropenethione underwent [4 + 2] cycloaddition with R,β-unsaturated thiones 289 and 290, to form 1,3-dithiins 291 and 292, respectively (eq 168). 276 Addition of two molecules of cycloproparene 293 occurred to the CdX bond (X ) O or S) of diphenylcyclopropenone or its sulfur analogue in the presence of Yb(fod) 3 catalyst (eq 169). 277 These reactions are consistent with the mechanism involving complexation of Yb(fod) 3 with an oxygen or sulfur atom and subsequent heterolytic cleavage of the cycloproparene ring.…”
Section: B Reaction At the CDX Double Bondmentioning
confidence: 99%
“…The formation of similar adducts has been observed from compounds containing a CdS bond. Treatment 276 The resulting intermediate, having a heterocyclic seven-membered ring, cleaved with a loss of arylketene (or sulfur atom) to give a thiophene (or a phenol). This is in contrast to the reactions of diphenylcyclopropenethione with 289 and 290, which produced 1,3-dithiins by addition to the CdS bond (eq 168).…”
Section: Addition With Cleavage Of C−c Single Bondmentioning
confidence: 99%
“…Diphenylcyclopropenethione underwent [4 + 2] cycloaddition with α,β-unsaturated thiones 289 and 290 , to form 1,3-dithiins 291 and 292 , respectively (eq 168) …”
Section: B Reaction At the Cx Double Bondmentioning
confidence: 99%
“…α,β-Unsaturated thiones 289 and 290 underwent [4 + 2] addition at the C−C single bond of cyclopropenone (eq 194) . The resulting intermediate, having a heterocyclic seven-membered ring, cleaved with a loss of arylketene (or sulfur atom) to give a thiophene (or a phenol).…”
Section: Addition With Cleavage Of C−c Single Bondmentioning
“…Diphenylcyclopropenethione underwent [4 + 2] cycloaddition with R,β-unsaturated thiones 289 and 290, to form 1,3-dithiins 291 and 292, respectively (eq 168). 276 Addition of two molecules of cycloproparene 293 occurred to the CdX bond (X ) O or S) of diphenylcyclopropenone or its sulfur analogue in the presence of Yb(fod) 3 catalyst (eq 169). 277 These reactions are consistent with the mechanism involving complexation of Yb(fod) 3 with an oxygen or sulfur atom and subsequent heterolytic cleavage of the cycloproparene ring.…”
Section: B Reaction At the CDX Double Bondmentioning
confidence: 99%
“…The formation of similar adducts has been observed from compounds containing a CdS bond. Treatment 276 The resulting intermediate, having a heterocyclic seven-membered ring, cleaved with a loss of arylketene (or sulfur atom) to give a thiophene (or a phenol). This is in contrast to the reactions of diphenylcyclopropenethione with 289 and 290, which produced 1,3-dithiins by addition to the CdS bond (eq 168).…”
Section: Addition With Cleavage Of C−c Single Bondmentioning
confidence: 99%
“…Diphenylcyclopropenethione underwent [4 + 2] cycloaddition with α,β-unsaturated thiones 289 and 290 , to form 1,3-dithiins 291 and 292 , respectively (eq 168) …”
Section: B Reaction At the Cx Double Bondmentioning
confidence: 99%
“…α,β-Unsaturated thiones 289 and 290 underwent [4 + 2] addition at the C−C single bond of cyclopropenone (eq 194) . The resulting intermediate, having a heterocyclic seven-membered ring, cleaved with a loss of arylketene (or sulfur atom) to give a thiophene (or a phenol).…”
Section: Addition With Cleavage Of C−c Single Bondmentioning
“…The o -thiobenzoquinone 119 thermally generated from the benzothiete 118 reacts with 2 to give monothioacetal 120 in a 4% yield (Scheme ) . A similar [2 + 4] cycloaddition reaction of thioketone 112 with α,β-unsaturated thiones 122 and 124 takes place to give dithioacetals 122 and 125 , respectively (Schemes and ) 66 67 68 69 …”
A [3 + 2]-cycloaddition reaction of in-situ-formed azaoxyallyl cations with cyclopropenones and cyclopropenethiones for the synthesis of biologically important spirocyclic oxazole and thiazole derivatives is reported. This concise procedure exhibited good functional group tolerance under very mild conditions and provided the corresponding spirocyclic products in good to excellent yields.Cycloaddition reaction is one of the most powerful strategies to build molecular complexity into carbocycles and heterocycles., [1] Since it was firstly prepared by the group of Breslow and the group of Vol'pin in 1959, [2] cyclopropenones have been extensively applied into cycloaddition reactions due to their high reactivity profile in the preparation of diverse cyclic molecules. [3] Generally, cyclopropenones involved cycloaddition reactions can be divided into the following three categories: (a) [3 + m]-cycloaddition of cyclopropenones by C1À C2 single bond cleavage (Scheme 1, path A); [4] (b) [2 + m]-cycloaddition of the C=C double bond(Scheme 1, path B); [5] (c) [2 + m]-cycloaddition of carbonyl moiety in cyclopropenones, thus leading to the formation of spirocyclic compounds (Scheme 1, path C). [6] The first strain release CÀ C bond cleavage processes are generally proceeded with the assistance with organo-or transition-metal catalysts. Compared with this most intriguing and well-developed [3 + m]-cycloaddition process, application of latter two types of [2 + m]-cycloaddition strategy is relatively overlooked, especially for synthesis spirocyclic compounds.In 2015, Werz and co-workers reported the synthesis of spirocyclic xanthene-cyclopropene scaffolds by using [2 + 2]cycloaddition of cyclopropenones with arynes as the key step. [6b] In the same year, Fernández, Sierra et al. realized a Lewis acid promoted [3 + 2]-cycloaddition of donor-acceptor cyclopropanes (DAC) with cyclopropenones, affording various biologically important 4-oxaspiro[2.4]hept-1-ene derivatives in [a] S.General procedure: A flame-dried flask equipped with a magnetic stir bar was charged with 1 a (1.0 equiv., 0.2 mmol), 2 a (2.0 equiv., 0.4 mmol), K 2 CO 3 (2.0 equiv., 0.8 mmol) and HFIP (2.0 mL). After that, the reaction mixture was stirred at 50°C for 12 h. The solvent was then removed under reduced pressure with the aid of a rotary evaporator. The crude residue was purified by silica gel column chromatography to afford pure product 3 a as a white solid in 70% yield.
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