1,3-Bis(silyloxy)-1,3-butadienes represent electroneutral equivalents of 1,3-dicarbonyl dianions. 1,1-Bis(silyloxy)ketene acetals can be regarded as masked carboxylic dianions. 1,3-bis(trimethylsilyloxy)alk-1-enes represent equivalents of dianions of β-hydroxyesters. All these building blocks undergo Lewis acid-mediated cyclization reactions with a variety of electrophiles.

Abstract: A variety of butenolides were prepared by cyclization of bis(silyl enol ethers), such as 1,3-bis(silyloxy)-1,3-butadienes, 1,3-bis(trimethylsilyloxy)alk-1-enes or 1,1-bis(silyloxy)ketene acetals, with oxalyl chloride. The products are of pharmacological relevance.

Review: Synlett 2006, 3369-3381.

Period of investigation: 1999 – 2009

Keywords: silyl enol ethers; cyclizations; heterocycles

Abstract: 4-(Silyloxy)benzopyrylium triflates can be readily generated in situ by reaction of chromones with trialkylsilyl-trifluoromethanesulfonate. Domino reactions of bis(silyl enol ethers) with such benzopyrylium triflates – derived from chromones, 3-cyanochromones and 3-formylchromones – allow for an efficient synthesis of a variety of carbo- and heterocycles.

Review: Synlett 2007, 1016-1025.

Period of investigation: 2001 - 2011

Keywords: silyl enol ethers; chromones; heterocycles

Abstract: The reaction of 1,3-bis(silyloxy)-1,3-butadienes with funcionalized and non-funcionalized acid chlorides and bis(acid chlorides) gives rise to the formation of a great variety of open-chained 1,3,5-tri- and 1,3,5,7-tetracarbonyl compounds and of cyclic products derived from them. Permethylated and cyclopropanated polycarbonyl compounds were successfully prepared by a stepwise protocol.

Review: Synlett 2021, 32, 2036-2045.

Period of investigation: 1999 - 2011

Keywords: silyl enol ethers; 1,3-dicarbonyl compounds

Abstract: 1,1-Bis(silyloxy)ketene acetals represent useful synthetic building blocks which can be regarded as masked carboxylic acid dianions. In recent years, a number of cyclization reactions of 1,1-bis(silyloxy)ketene acetals have been reported which provide a convenient synthesis of various pharmacologically relevant heterocyclic products.

Review: Synlett 2012, 23, 1283-1290.

Period of investigation: 2005 - 2008

Keywords: silyl enol ethers; heterocycles; cyclizations

Abstract: Lewis acid mediated [3+3] cyclizations of 1,3-bis(silyl enol ethers) with 1,3-dielectrophiles, such as 1,1,3,3-tetramethoxypropane, 3-silyloxy-2-en-1-ones and 1,1-diacylcyclopropanes, provide an efficient approach to a variety of functionalized arenes (such as salicylates and phenols) and other six-membered carbocyclic products which are of pharmacological relevance.

Review: Synthesis 2007, 327-347.

Period of investigation: 2002 – 2014

Keywords: silyl enol ether; cyclizations; arenes

Abstract: Formal [3+3] cyclocondensation reactions of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with functionalized and non-functionalized 1-alkyl- and 1-aryl-3-alkoxy-2-en-1-ones, 1,1-dichloro-3-buten-2-ones, 3-acyl-4,5-dihydrofurans and other related 1,3-dielectrophiles provide a convenient and regioselective approach to various highly substituted, functionalized phenols.

Review: Curr. Org. Chem. 2012, 16, 557-565.

Period of investigation: 2004 – 2014

Keywords: silyl enol ether; cyclizations; arenes

Abstract: Cyclocondensation reactions of sulfur-containing dienes, such as 3-arylthio-1-silyloxy-1,3-butadienes and 4-arylthio-1,3-bis(trimethylsilyloxy)-1,3-butadienes, with various dielectrophiles and dieneophiles allow for a convenient synthesis of a variety of functionalized and sterically encumbered aryl-substituted sulfides and sulfones.

Review: Synlett 2010, 2383-2391.

Period of investigation: 2005 - 2014

Keywords: silyl enol ethers; cyclizations; arenes

Abstract: One-pot cyclizations of fluorinated 1,3-bis(silyloxy)-1,3-butadienes and 3-alkoxy- and 3-silyloxy-2-en-1-ones provide a convenient access to various fluoro-, trifluoromethyl- and perfluoroalkyl-substituted arenes and hetarenes.

Review: Synlett 2019, 30, 665-773.

Period of investigation: 2005 - 2010

Keywords: silyl enol ethers; cyclizations; arenes; heterocycles