Reactions of bromine-containing organozinc compounds derived from α,α-dibromo ketones with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones

Abstract

Bromine-containing organozinc compounds generated from 1,1-dibromo-3,3-dimethylbutan-2-one reacted with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones to give 3-aryl-2-(2,2-dimethylpropanoyl)spiro[cyclopropane-1,2′-indan]-1′,3′-diones and 1-aryl-6,6-dimethyl-2-(2,2-dimethylpropanoyl)-5,7-dioxaspiro[2.5]octan-4,8-diones, respectively. Reactions of 2-arylmethylideneindan-1,3-diones with bromine-containing zinc enolates derived from 1-aryl-2,2-dibromopropan-1-ones and 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one resulted in the formation of 2-aroyl-3-aryl-2-methylspiro-[cyclopropane-1,2′-indan]-1′,3′-diones and 2,3 : 8,9-dibenzo-12-phenyldispiro[4.0.5.1]dodecane-1,4,7-trione, respectively.We previously developed a procedure for the synthesis of spirocyclopropanes via reaction of 3-aryl-2-cyanoprop-2-enoic acid derivatives with zinc enolates derived from 2,2-dibromo-1,2,3,4-tetrahydronaphthalen-1-one and 2,2-dibromoindan-1-one [1]. In the present work we made an attempt to find out another synthetic approach to cyclopropane derivatives having one and two spiro carbon atoms. For this purpose, we examined reactions of bromine-containing organozinc compounds derived from α,α-dibromo ketones with 2-arylmethylideneindan-1,3-diones and 5-arylmethylidene-2,2-dimethyl-1,3-dioxane-4,6-diones. In fact, these reactions led to the formation of the corresponding cyclopropanation products as shown in Scheme 1.Zinc enolate II preliminarily generated from 1,1-dibromo-3,3-dimethylbutan-2-one I added at the double C=C bond in substrates IIIa, IIIb, IVa, and IVb to give intermediates Va, Vb, VIIa, and VIIb which underwent cyclization with formation of cyclopropanation products, 1-aryl-6,6-dimethyl-2-(2,2-dimethylpropanoyl)-5,7-dioxaspiro[2.5]octane-4,8-diones VIa and VIb and 3-aryl-2-(2,2-dimethylpropanoyl)spiro[cyclopropane-1,2 ′ -indan]-1′,3′-diones VIIIa and VIIIb (Scheme 1).

Diastereoselective Synthesis of Spirocyclopropanes under Mild Conditions via Formal [2 + 1] Cycloadditions Using 2,3-Dioxo-4-benzylidene-pyrrolidines

“…For instance, the ring-enlargement reactions of cyclopropanes with nucleophiles, such as amines, alcohols, and carboxylic acids, are efficient pathways to various heterocycles [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. Consequently, numerous efforts have been devoted to the formation of three-membered carbocyclic rings during the last few decades [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 ]. The reactions of carbenoids with alkenes such as the Simmons–Smith cyclo-propanation involving organozinc carbenes [ 37 , 38 , 39 , 40 ], or the addition of carbenes, generated from diazo compounds in the presence of transition metals, to double bonds [ 41 , 42 , 43 , 44 ] are the most significant and useful classical methods for the construction of cyclopropanes.…”

N-Iodosuccinimide-Initiated Spirocyclopropanation of Styrenes with 1,3-Dicarbonyl Compound for the Synthesis of Spirocyclopropanes

“…8 In 2009, the Wang group reported the oxidative addition reaction of various aldehydes with 5,5-dimethylcyclohexane-1,3-dione and 1,3-indanedione to selectively afford spirocyclopropane derivatives, promoted by molecular iodine and dimethylaminopyridine under mechanical milling conditions (Scheme 1b). 9 Such spirocyclopropane also could be prepared from 2-arylmethylideneindan-1,3-diones with α-monohalogenated active methylene compounds via a base-promoted MIRC (Michael-induced ring closure) approach 10 or bromine-containing zinc enolates intermediate 11 (Scheme 1c). However, these methods generally require the pregeneration of reagents or harsh reaction conditions, which lowers the synthetic efficiency and limits the practical application.…”