Efficient strategy for construction of 6-carbamoylfulvene-6-carboxylate skeletons via [3 + 2] cycloaddition of 1-cyanocyclopropane 1-ester with β-nitrostyrenes

Abstract

An efficient and straightforward the preparation of 6-carbamoylfulvene-6-carboxylates via a cycloaddition reaction between 1-cyanocyclopropane 1-ester and β-nitrostyrenes.

Novel synthesis of highly functionalized cyclopentane derivatives via [3 + 2] cycloaddition reactions of donor–acceptor cyclopropanes and (E)-3-aryl-2-cyanoacrylates

“…In order to explore the optimal reaction conditions, we began our investigation by studying the [3 + 2] annulation of D-A cyclopropane 1a and (E)-3-aryl-2-cyanoacrylates 2a. Initially, based on our more recent results, 24,26,[28][29][30] the reaction of D-A cyclopropane 1a (1.0 mmol) and (E)-3aryl-2-cyanoacrylates 2a (1.2 mmol) was examined in dichloromethane (15 mL) using trimethylamine (1 equiv.) as a promoter for 12 h under reflux, and the desired product 3a was obtained in only 35% yield.…”

“…First, in the presence of DBU, the deprotonation of D-A cyclopropane 1a-i affords a cyclopropan-1-ide [A], which undergoes opening ring to produce prop-2-en-1-ide [B]. 28 24 Finally, the enol-keto tautomerism of [C] mediated by base DBU yields the products 3a-j.…”

“…[24][25][26][27] Among them is an efficient and straightforward synthetic protocol for the preparation of fully substituted cyclopentadienes via [3 + 2] cycloaddition of 1-cyanocyclopropane-1-carboxy esters with β-nitrostyrenes. 28 In continuation of our interests in constructing the heterocycles and carbocycles, based on our studies on the reactivity of 2-aroyl-3-aryl-1-cyanocyclopropane carbonates, we envisioned that the reaction of 2-aroyl-3-aryl-1-cyanocyclopropane carbonates with substituted 3-aryl -2-cyanoacrylates may offer an efficient approach to cyclopentane skeletons via [3 + 2] cycloadditions. Herein, we report a new approach for the synthesis of highly functionalized cyclopentane derivatives via a simple [3 + 2] cycloaddition reaction of cyanocyclopropanecarbonates and (E)-3-aryl-2-cyanoacrylates.…”

“…The crystallographic data of 3d and 3g are listed in Table2.Based on the above experimental results, a possible mechanism is proposed in Scheme 1. First, in the presence of DBU, the deprotonation of D-A cyclopropane 1a-i affords a cyclopropan-1-ide [A], which undergoes opening ring to produce prop-2-en-1-ide [B] 28. Next, [3 + 2] annulation via crossing nucleophilic addition of intermediate prop-2-en-1-ide [B] and (E)-3-aryl-2-cyanoacrylates 2a-f gives 1,3-dicyano-4-(hydroxymethylene)-2,5-diphenylcyclopentane-1,3-dicarboxylate [C] 24.…”

Stereoselective Synthesis of 4,5‐Dihydroisoxazole Derivatives from 1,1‐Dicyanocyclopropanes and Hydroxylamine Hydrochloride

“…to construct various carbo‐ and heterocyclic compounds, containing many natural compounds and their analogs. As easily available multifunctional D‐A cyclopropanes, 2‐acyl‐3‐aryl‐cyclo‐propane‐1,1‐dicarbonitriles and 2‐acyl‐3‐aryl‐1‐cyanocyclopropane‐1‐carboxylates [84–96] have attracted wide attention in the classical heterocycle syntheses [97–112] . Considering the driving forces for the development of these new routes, and in continuation of using multifunctional D‐A cyclopropanes in the synthesis of diverse and complex compounds, we envisioned an approach to access functionalized isoxazoline derivatives through a cyclization reaction of substituted 1,1‐dicyanocyclopropane derivatives and hydroxylamine hydrochloride.…”