Mathematisch-Naturwissenschaftliche Fakultät

Institut für Chemie

Fachgebiet: Preparative Organic Chemistry

Betreuer: Prof. Dr. Peter Langer

Mr Muhammad Adeel
(e-mail: )

Synthesis of functionalized biaryls, benzophenones, phenols, fluorenones, fluoroarenes and chloroarenes based on formal [3+3] cyclocondensations of 1,3-bis(silyloxy)-1,3-butadienes and 1,3,5-tris(silyloxy)-1,3,5-hexatrienes.

Chapter (1) contains the synthesis of Highly functionalized polyketide-type phenols which were prepared by domino ′Michael / retro-Michael / aldol′ reactions of 3-formylchromones with 1-ethoxy-1,3,5-tris(trimethylsilyloxy)-1,3,5-hexatriene and its synthetic precursor, ethyl 3,5-bis(trimethylsilyloxy)-2,4-hexadienoate.

Chapter (2) includes the synthesis of Sterically encumbered biaryls which were regioselectively prepared based on formal [3+3] cyclocondensations of novel 4-aryl-1,3-bis(trimethylsilyloxy)-1,3-dienes. Chapter (3) contains the synthesis of Functionalized fluorenones which were efficiently prepared in four steps. 1-hydroxyfluorenones were prepared by [3+3] cyclization of 3-aryl-3-(silyloxy)-2-en-1-ones with 1,3-bis(silyloxy)buta-1,3-dienes and subsequent intramolecular Friedel–Crafts acylation of the 6-arylsalicylates.

Chapter (4) contains the reactions of first fluorine containing 1,3-bis(silyl enol ether), the reactions of with epichlohydrin, 2,3-butenoxide, cyanochromones and phathaloyl dichloride resulted in several novel fluorinated compounds which are not readily available by other methods.

Chapter (5) is concerned with reactions of 2-chloro-1,3-bis(trimethylsilyloxy)-1,3-butadienes with epibromo and epichlorohydrin, 2,3butenoxide, cyanochromones and DMAD allow a convenient synthesis of chlorinated molecules such as which are not readily available by other methods.

Chapter (6) includes the synthesis of chlorinated biaryls, azaxanthones, benzotropones, and isobenzofurans which were prepared by one-pot cyclizations 1-alkoxy-4-chloro-1,3-bis(trimethylsilyloxy)-1,3-butadienes with various dielectrophiles. In chapter 7 we have reported Acetal-protected (2,4-dioxocyclohex-1-yl)-acetic acids which were prepared by allylation of dilithiated 1,3-cyclohexane-1,3-diones, protection of the carbonyl groups and oxidation of the alkene moiety. Their reaction with amines afforded the corresponding amides which were transformed, by acid-catalyzed cyclization, into various 2,6-dioxo-1,2,3,4,5,6-hexahydroindoles. The reaction of the corresponding amides with triflic acid resulted in the formation of novel 5,8,9,10-tetrahydro-6H-indolo [2,1-a]isoquinolin-9-ones.