Adventures in the Chemistry of 1,1-Diacylcyclopropanes

Abstract

The present personalized account aims to highlight 1,1-diacylcyclopropanes as synthetic building blocks or target molecules. The chemistry presented includes cyclization reactions of 1,1-diacylcyclopropanes with free and masked dianions to give spirocyclopropanes as products or reactive intermediates that readily undergo ring-cleavage reactions. In addition, the synthesis of cyclopropylated 1,3,5-tricarbonyl compounds, containing two 1,1-diacylcyclopropane moieties, is discussed. Based on this work also other syntheses of cyclopropanes were developed.1 Introduction2 Reactions of Masked Dianions3 Reactions of Free Dianions4 Cyclopropylated 1,3,5-Tricarbonyl Compounds5 Miscellaneous6 Conclusions

Domino reactions of chromones with activated carbonyl compounds

“…Dianions of 1,3-dicarbonyl compounds follow a different regioselectivity as compared to simple monoanions [6][7][8][9][10][11][12]. For example, 2 can be transformed to its dianion 7 by action of two equivalents of LDA or by sequential addition of sodium hydride and n-butyllithium (Scheme 1).…”

Small and Smart: Adventures in Epihalohydrin Chemistry

“…During the early years of my independent career at the University of Göttingen under the mentorship of Professor Armin de Meijere, I was interested in the development of cyclization reactions of 1,3-dicarbonyl dianions (so-called free dianions) and of 1,3-bis(silyloxy)-1,3-butadienes, which can be represented as electroneutral equivalents of dianions (so-called masked dianions). 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Monoanion A of ethyl acetoacetate ( 2a ) usually undergoes reactions with electrophiles at the central carbon atom of the 1,3-dicarbonyl moiety (Scheme 2 ). In contrast, the employment of dianion B , which can be generated in situ from 2a by treatment with two equivalents of LDA or by sequential addition of sodium hydride and butyllithium, permits functionalization at the terminal carbon atom.…”