How to Synthesize Easily Dimethyl (2R) and (2S)-Formylcyclopropane-1,1-dicarboxylate, a Precursor of a Wide Variety of Substituted Aminocyclopropanecarboxilic Acids

Synthesis and Radical Polymerization of Various 2‐Cyclopropylacrylates

“…Pentane, hexane, 1,3-cyclohexadiene, tert-butyl methyl ether, oxalyl chloride, methyl and ethyl chlorooxalate, lithium hydroxide monohydrate, sodium cyanide, activated manganese() oxide, 10 wt.-% Pd/C, dirhodium tetraacetate, methyltriphenylphosphonium bromide, potassium tert-butoxide, n-butyllithium solution in hexane, 2,6-ditert-butyl-4-methylphenol (BHT), dimethyl trans-cyclopropane-1,2-dicarboxylate (3d) and aliphatic urethane dimethacrylate (UDMA, Ivoclar Vivadent, from 2-hydroxyethyl methacrylate and 2,2,4-trimethylhexamethylenediisocyanate) were used as supplied without further purification. 1,1-Bis(ethoxycarbonyl)-2-vinylcyclopropane [17] (DECVCP), methylenecyclopropane [18] (2b), bicyclopro-pylidene [19] (2c), dimethyl bicyclo[3.1.0]hexane-6,6-dicarboxylate [20] (3f), diethyl 2-formylcyclopropane-1,1-dicarboxylate [7] (5e), potassium cyclopropyloxoacetate, [21] methyl and ethyl diazopyruvate, [22] 3,3-dimethylcyclobutyl bromide, [23] ethyl trans-(2-ethenylcyclopropyl)oxoacetate (7g) and ethyl trans-2-(2-ethenylcyclopropyl)-propenoate [13] (1g) were prepared as described previously. 2,2Ј-Azobisisobutyronitrile (AIBN) was purified by recrystallization from methanol.…”

“…The aldehyde 5e was prepared in 83% yield according to a previously reported procedure. [7] For the preparation of aldehydes 5d,f a new saponification protocol for dimethyl cyclopropanedicarboxylates 3d,f leading to halfesters 4d,f in high yields and, in the case of 3f, with excellent regioselectivity, was developed. Thus, the bicyclic gem-diester 3f was hydrolyzed with lithium hydroxide monohydrate, suspended in a mixture of tetrahydrofuran and methanol (4:1), to give only the exo-carboxylic acid 4f in 83% yield, the configuration of which was also confirmed by an X-ray crystal structure analysis.…”

“…Taking into consideration the fact that the molar composition of a copolymer of DECVCP and MMA obtained under similar conditions [4] was 0.09:1.00, it can be concluded that the 2-cyclopropylacrylates, especially the bicyclic monomers 1h and 1k, demonstrate a drastically im- proved reactivity in the radical polymerization when compared to DECVCP. [17] (DECVCP), methylenecyclopropane [18] (2b), bicyclopro-pylidene [19] (2c), dimethyl bicyclo[3.1.0]hexane-6,6-dicarboxylate [20] (3f), diethyl 2-formylcyclopropane-1,1-dicarboxylate [7] (5e), potassium cyclopropyloxoacetate, [21] methyl and ethyl diazopyruvate, [22] 3,3-dimethylcyclobutyl bromide, [23] ethyl trans-(2-ethenylcyclopropyl)oxoacetate (7g) and ethyl trans-2-(2-ethenylcyclopropyl)propenoate [13] (1g) were prepared as described previously. 2,2Ј-Azobisisobutyronitrile (AIBN) was purified by recrystallization from methanol.…”

Functionalized Cyclopropanes as Versatile Intermediates for the Diversity-Oriented Synthesis of γ-Lactones, γ-Lactams and δ-Lactams

“…Later, Le Goffic and co-workers reported a method for the preparation of an analogue of Ι in 60% yield, from acrolein and methyl bromomalonate, by replacing NaOEt with K 2 CO 3 as the base. 18 More recently, methodologies involving the use of organocatalysis for the enantioselective cyclopropanation of ,-unsaturated aldehydes have been described. [19][20][21] Scheme 1 Synthesis of functionalized cyclopropane-1,1-diesters Our group 22,23 SYNTHESIS0 0 3 9 -7 8 8 1 1 4 3 7 -2 1 0 X Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart 2021, 53, A-N 1 through a domino cyclopropanation/lactonization/aminolysis process.…”

Development of Viable Synthetic Approaches to Highly Functionalized Small Ring Systems - Synthesis of Novel Cyclopropylacrylates as Monomers for Low-Shrinkage Polymer-Composites

“…Finally, condensation of diethyl α-bromomalonate (78) with 2-propenal (79) conducted according to literature [63] gave 2-formyl-1,1-cyclopropanedicarboxylic acid diethyl ester (80) in high yield (Scheme 34). Surprisingly, yield of the presented reaction was significantly higher than the reported one (60%) for the corresponding dimethyl α-bromomalonate used in the original procedure.…”