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Abstract: Functionalized mono-protected p-dihydrobenzoquinones were prepared by [3+3] cyclization of 1,3-bis-silyl enol ethers with 2-acyloxy-3-(silyloxy)alk-2-en-1-ones. Deprotection and oxidation of the products afforded the corresponding p-benzoquinones. [Copyright &y& Elsevier]

A variety of 5-chlorosalicylates were prepared by regio�selective one-pot cyclizations of 1,3-bis(trimethylsilyloxy)buta-1,3-dienes with novel 2-chloro-3-ethoxy-2-alken-1-ones. [ABSTRACT FROM AUTHOR]

Abstract: Functionalized 2,5-dihydrobenzo[b]oxepins and 5,6-dihydro-2H-benzo[b]oxocines were prepared based on a ‘[3+3] cyclization–olefin-metathesis’ strategy. [Copyright &y& Elsevier]

Abstract: 6-(Perfluoroalkyl)salicylates were prepared by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 3-ethoxy-1-(perfluoroalkyl)prop-2-en-1-ones. [Copyright &y& Elsevier]

Abstract: 1,4-Diaza-7-oxabicyclo[4.3.0]non-2-en-6-ones were prepared by cyclization of 1,1-bis(trimethylsiloxy)ketene acetals with pyrazine and quinoxaline. [Copyright &y& Elsevier]

Abstract: The TiCl4-mediated [3+3] cyclization of 2,4-bis(trimethylsilyloxy)penta-1,3-diene with 3-silyloxyalk-2-en-1-ones afforded 2-acetylphenols, which were transformed into functionalized chromones. The Me3SiOTf-mediated condensation of the latter with 1,3-bis(silyl enol ethers) and subsequent domino ‘retro-Michael–aldol–lactonization’ reaction afforded 7-hydroxy-6H-benzo[c]chromen-6-ones. [Copyright &y& Elsevier]

Abstract: The cyclization of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with 3-oxo-bis(methylthio)ketenacetals afforded 3-(methylthio)phenols containing an acyl or ester substituent located at position 2. The cyclization of free 1,3-dicarbonyl dianions with 3-oxo-bis(methylthio)ketenacetals resulted in the formation of regioisomeric products containing an acyl group located at position 6. [Copyright &y& Elsevier]

Abstract: Sterically encumbered biaryls are prepared in two steps by combination of the CuI–proline-catalyzed arylation of acetylacetone with formal [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-dienes. In addition, the synthesis of 4,6- and 5,6-diarylsalicylates based on [3+3] cyclizations is reported. [Copyright &y& Elsevier]

Abstract: The [3+3] cyclization of 1,3-bis(silyloxy)-1,3-butadienes with 1-hydroxy-5-silyloxy-hex-4-en-3-ones resulted in the one-pot formation of 3-aryl-3,4-dihydroisocoumarins. The reactions proceeded by regioselective cyclization to give 6-(2-aryl-2-chloroethyl)salicylates, which underwent a silica gel-mediated lactonization. The cyclizations of protected 1-amino-5-silyloxy-hex-4-en-3-ones proved to be not regioselective. [Copyright &y& Elsevier]

Abstract: Functionalized triarylmethanes are prepared in two steps by FeCl3-catalyzed benzylation of acetylacetone to give 3-(diarylmethyl)pentane-2,4-diones and subsequent formal [3+3] cyclization of the latter with 1,3-bis(trimethylsilyloxy)-1,3-dienes. [Copyright &y& Elsevier]

Abstract: Functionalized amino- and nitro-substituted biaryls and dibenzo[b,d]pyrid-6-ones (6(5H)-phenanthridinones) were prepared by [3+3]cyclocondensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with nitro-substituted 1-aryl-1-silyloxy-1-en-3-ones and subsequent hydrogenation. 4-Nitro- and 4-aminophenols were prepared based on formal [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with 3-ethoxy-2-nitro-2-en-1-ones. [Copyright &y& Elsevier]

Abstract: A variety of 2-arylthio-4-methoxybenzoates are regioselectively prepared by TiCl4-mediated [3+3] cyclocondensations of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 3-oxo-orthoesters. Unsubstituted 2-(arylthio)benzoates were prepared by Me3SiOTf-catalyzed cyclization of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 1,1,3,3-tetramethoxypropane. The TiCl4-mediated cyclization of 3-arylthio-1-trimethylsilyloxy-1,3-butadienes with 1,1-bis(methylthio)-1-en-3-ones results in regioselective formation of 2-arylthio-6-(methylthio)benzoates. [Copyright &y& Elsevier]

Abstract: Hetero-Diels–Alder reactions of 1,3-bis(silyloxy)-1,3-butadienes with arylsulfonylcyanides afforded a variety of 4-hydroxy-2-(arylsulfonyl)pyridines. Several derivatives show antimicrobial activity against Gram-positive bacteria. [Copyright &y& Elsevier]

Abstract: Functionalized diaryl sulfides were prepared based on one-pot cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes. [Copyright &y& Elsevier]

Abstract: Functionalized and sterically encumbered diaryl ethers were prepared by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 2-aryloxy-3-(silyloxy)alk-2-en-1-ones. [Copyright &y& Elsevier]

Abstract: Functionalized 3-hydroxymaleic anhydrides were prepared by cyclization of 1,1-bis(trimethylsilyloxy)ketene acetals with oxalyl chloride. [Copyright &y& Elsevier]

Abstract: The domino, Michael–retro-Michael–aldol, reaction of 2,4-bis(trimethylsilyloxy)penta-1,3-diene with 3-formylchromones afforded 4-(2-hydroxybenzoyl)-2-acetylphenols, which were transformed into 6-(2-hydroxybenzoyl)chromones. The Me3SiOTf-mediated condensation of the latter with 1,3-bis(silyl enol ethers) and subsequent domino ‘retro-Michael–aldol–lactonization’ reaction afforded 7-hydroxy-2-(2-hydroxybenzoyl)benzo[c]chromen-6-ones. [Copyright &y& Elsevier]