In recent years, the chemistry of cyclopropanes and cyclopropenes has experienced a renaissance. Novel asymmetric methods to prepare and use these strained molecules are now accessible. Moreover, cyclopropane and cyclopropene derivatives have found interesting applications in catalysis, have shown to be excellent biorthogonal chemical reporters and are playing an increasing role in drug discovery. This thematic issue intends to cover a broad spectrum of articles on the chemistry and applications of these fascinating compounds.
Graphical Abstract
Scheme 1: (a) General metal-catalyzed olefin cyclopropanation reaction with diazo compounds. (b) The ethylene...
Scheme 2: Routes toward ethyl cyclopropanecarboxylate (1). (a) Ethylene cyclopropanation described by De Brui...
Figure 1: Effect of the pressure of ethylene on the yields of ethyl cyclopropanecarboxylate in the reaction o...
Graphical Abstract
Scheme 1: The oxidative radical ring-opening/cyclization of cyclopropane derivatives.
Scheme 2: Mn(OAc)3-mediated oxidative radical ring-opening and cyclization of MCPs with malonates.
Scheme 3: Mn(III)-mediated oxidative radical ring-opening and cyclization of MCPs with 1,3-dicarbonyl compoun...
Scheme 4: Heat-promoted ring-opening/cyclization of MCPs with elemental chalgogens.
Scheme 5: Copper(II) acetate-mediated oxidative radical ring-opening and cyclization of MCPs with diphenyl di...
Scheme 6: AIBN-promoted oxidative radical ring-opening and cyclization of MCPs with benzenethiol.
Scheme 7: AIBN-mediated oxidative radical ring-opening and cyclization of MCPs with diethyl phosphites.
Scheme 8: Organic-selenium induced radical ring-opening and cyclization of MCPs derivatives (cyclopropylaldeh...
Scheme 9: Copper(I)-catalyzed oxidative radical trifluoromethylation/ring-opening/cyclization of MCPs with To...
Scheme 10: Ag(I)-mediated trifluoromethylthiolation/ring-opening/cyclization of MCPs with AgSCF3.
Scheme 11: oxidative radical ring-opening and cyclization of MCPs with α-C(sp3)-–H of ethers.
Scheme 12: Oxidative radical ring-opening and cyclization of MCPs with aldehydes.
Scheme 13: Cu(I) or Fe(II)-catalyzed oxidative radical trifluoromethylation/ring-opening/cyclization of MCPs d...
Scheme 14: Rh(II)-catalyzed oxidative radical ring-opening and cyclization of MCPs.
Scheme 15: Ag(I)-catalyzed oxidative radical amination/ring-opening/cyclization of MCPs derivatives.
Scheme 16: Heating-promoted radical ring-opening and cyclization of MCP derivatives (arylvinylidenecyclopropan...
Scheme 17: Bromine radical-mediated ring-opening of alkylidenecyclopropanes.
Scheme 18: Fluoroalkyl (Rf) radical-mediated ring-opening of MCPs.
Scheme 19: Visible-light-induced alkylation/ring-opening/cyclization of cyclopropyl olefins with bromides.
Scheme 20: Mn(III)-mediated ring-opening and [3 + 3]-annulation of cyclopropanols and vinyl azides.
Scheme 21: Ag(I)-catalyzed oxidative ring-opening of cyclopropanols with quinones.
Scheme 22: Ag(I)-catalyzed oxidative ring-opening of cyclopropanols with heteroarenes.
Scheme 23: Cu(I)-catalyzed oxidative ring-opening/trifluoromethylation of cyclopropanols.
Scheme 24: Cu(I)-catalyzed oxidative ring-opening and trifluoromethylation/trifluoromethylthiolation of cyclop...
Scheme 25: Ag(I)-mediated oxidative ring-opening/fluorination of cyclopropanols with Selectfluor.
Scheme 26: Photocatalyzed ring-opening/fluorination of cyclopropanols with Selectfluor.
Scheme 27: Na2S2O8-promoted ring-opening/alkynylation of cyclopropanols with EBX.
Scheme 28: Ag(I)-catalyzed ring-opening and chlorination of cyclopropanols with aldehydes.
Scheme 29: Ag(I)-catalyzed ring-opening/alkynylation of cyclopropanols with EBX.
Scheme 30: Na2S2O8-promoted ring-opening/alkylation of cyclopropanols with acrylamides.
Scheme 31: Cyclopropanol ring-opening initiated tandem cyclization with acrylamides or 2-isocyanobiphenyls.
Scheme 32: Ag(II)-mediated oxidative ring-opening/fluorination of cyclopropanols with AgF2.
Scheme 33: Cu(II)-catalyzed ring-opening/fluoromethylation of cyclopropanols with sulfinate salts.
Scheme 34: Cu(II)-catalyzed ring-opening/sulfonylation of cyclopropanols with sulfinate salts.
Scheme 35: Na2S2O8-promoted ring-opening/arylation of cyclopropanols with propiolamides.
Scheme 36: The ring-opening and [3 + 2]-annulation of cyclopropanols with α,β-unsaturated aldehydes.
Scheme 37: Cu(II)-catalyzed ring-opening/arylation of cyclopropanols with aromatic nitrogen heterocyles.
Scheme 38: Ag(I)-catalyzed ring-opening and difluoromethylthiolation of cyclopropanols with PhSO2SCF2H.
Scheme 39: Ag(I)-catalyzed ring-opening and acylation of cyclopropanols with aldehydes.
Scheme 40: Aerobic oxidation ring-opening of cyclopropanols for the synthesis of 2-oxyranyl ketones.
Scheme 41: Aerobic oxidation ring-opening of cyclopropanols for the synthesis of linear enones.
Scheme 42: Aerobic oxidation ring-opening of cyclopropanols for the synthesis of metabolite.
Graphical Abstract
Scheme 1: Typical syntheses of 1,2-divinylcyclopropanes and rationale hypothesis for their syntheses from cyc...
Scheme 2: Synthesis of 1,2-divinylcyclopropane 3a: Optimization studies. aIsolated yield. bDetermined by 1H N...
Scheme 3: Synthesis of 1,2-divinylcyclopropanes 3 from cyclopropenes 1 and unbiased 1,3-dienes 2: Scope. (Yie...
Scheme 4: Rh-catalyzed intramolecular cyclopropanation with dienylcyclopropene 4 (the trans/cis ratio is rela...
Scheme 5: Zn- or Rh-catalyzed reactions of cyclopropenes 1 with furan (6) and 1,4-cyclohexadiene (8) and comp...
Graphical Abstract
Scheme 1: Representative strategies for the formation of alkylidenecyclopropanes from cyclopropenes and scope...
Scheme 2: [2,3]-Sigmatropic rearrangement of phosphinites 2a–h.
Scheme 3: [2,3]-Sigmatropic rearrangement of a phosphinite derived from enantioenriched cyclopropenylcarbinol...
Scheme 4: Selective reduction of phosphine oxide (E)-3f.
Scheme 5: Attempted thermal [2,3]-sigmatropic rearrangement of phosphinite 6a.
Scheme 6: Computed activation barriers and free enthalpies.
Scheme 7: [2,3]-Sigmatropic rearrangement of phosphinites 6a–j.
Scheme 8: Proposed mechanism for the Lewis base-catalyzed rearrangement of phosphinites 6.
Scheme 9: [3,3]-Sigmatropic rearrangement of tertiary cyclopropenylcarbinyl acetates 10a–c.
Scheme 10: [3,3]-Sigmatropic rearrangement of secondary cyclopropenylcarbinyl esters 10d–h.
Scheme 11: [3,3]-Sigmatropic rearrangement of trichoroacetimidates 12a–i.
Scheme 12: Reaction of trichloroacetamide 13f with pyrrolidine.
Scheme 13: Catalytic hydrogenation of (arylmethylene)cyclopropropane 13f.
Scheme 14: Instability of trichloroacetimidates 21a–c derived from cyclopropenylcarbinols 20a–c.
Scheme 15: [3,3]-Sigmatropic rearrangement of cyanate 27 generated from cyclopropenylcarbinyl carbamate 26.
Scheme 16: Synthesis of alkylidene(aminocyclopropane) derivatives 30–37 from carbamate 26.
Scheme 17: Scope of the dehydration–[3,3]-sigmatropic rearrangement sequence of cyclopropenylcarbinyl carbamat...
Scheme 18: Formation of trifluoroacetamide 50 from carbamate 49.
Scheme 19: Formation of alkylidene[(N-trifluoroacetylamino)cyclopropanes] 51–54.
Scheme 20: Diastereoselective hydrogenation of alkylidenecyclopropane 51.
Scheme 21: Ireland–Claisen rearrangement of cyclopropenylcarbinyl glycolates 56a–l.
Scheme 22: Synthesis and Ireland–Claisen rearrangement of glycolate 61 possessing gem-diester substitution at ...
Scheme 23: Synthesis of alkylidene(gem-difluorocyclopropanes) 66a–h, and 66k–n from propargyl glycolates 64a–n....
Scheme 24: Ireland–Claisen rearrangement of N,N-diBoc glycinates 67a and 67b.
Scheme 25: Diastereoselective hydrogenation of alkylidenecyclopropanes 58a and 74.
Scheme 26: Synthesis of functionalized gem-difluorocyclopropanes 76 and 77 from alkylidenecyclopropane 66a.
Scheme 27: Access to oxa- and azabicyclic compounds 78–80.
Graphical Abstract
Figure 1: A comparison of the solubility of Ru(II)-Pheox (cat. 1) and Ru(II)-Amm-Pheox (cat. 2).
Scheme 1: Intramolecular cyclopropanation of various trans-allylic diazo Weinreb amide derivatives catalyzed....
Scheme 2: Synthetic transformation of cyclopropane products 2d and 2f.
Graphical Abstract
Scheme 1: Applications of N-arylaminocyclopropanes.
Scheme 2: Synthesis of trans-ethyl 2-aminocyclopentanecarboxylate.
Scheme 3: Proposed mechanism.
Graphical Abstract
Figure 1: Cyclopropene-modified mannosamine, glucosamine and galactosamine derivatives employed for MGE.
Figure 2: A) Reaction of ManNCyc and ManNCp, respectively, with Tz-PEG-OH to determine second-order rate cons...
Scheme 1: MGE with cyclopropene-modified mannosamines. Cells were grown with sugar for 48 hours and then incu...
Figure 3: HEK 293T cells were grown with 100 μM Ac4ManNCyc, Ac4ManNCp, Ac4ManNCyoc or DMSO only (negative con...
Scheme 2: Synthesis of Ac4ManNCp(H2) and Ac4ManNCyc(H2) and the corresponding DMB-labeled sialic acids. C/A =...
Scheme 3: Synthesis of Ac4ManNCyoc(H2) and the corresponding DMB-labeled sialic acid.
Scheme 4: Synthesis of Ac4GlcNCp and Ac4GalNCp.
Figure 4: HEK 293T cells were grown with 100 μM Ac4ManNCp, Ac4GlcNCp, Ac4GalNCp or DMSO only (negative contro...
Figure 5: HEK 293T cells were grown with 100 μM Ac4GlcNCp, Ac4GalNCp or DMSO only (negative control) for 48 h...
Figure 6: HEK 293T cells were grown with 50 μM (A) or 100 μM (B) Ac4GlcNCp, Ac4GlcNCyoc or DMSO only (negativ...
Figure 7: Western blot analysis of soluble glycoproteins. HEK 293T cells were grown for 48 h with 100 μM Ac4M...
Scheme 5: Synthesis of Ac4GlcNCp(H2) and Ac4GlcNCyoc(H2).
Graphical Abstract
Scheme 1: Various strategies leading to the formation of cyclopropanols.
Scheme 2: General approach to the preparation of cyclopropanol and cyclopropylamine derivatives.
Figure 1: Prerequisite for a regio- and diastereoselective carbometalation.
Scheme 3: Preparation of cyclopropenyl methyl ethers 3a–d.
Scheme 4: Regio- and diastereoselective carbocupration of cyclopropenyl methyl ethers 3a,c.
Scheme 5: Diastereoselective formation of cyclopropanols.
Scheme 6: Diastereoselective carbometalation/oxidation of nonfunctionalized cyclopropenes 6.
Scheme 7: Preparation of diastereoisomerically pure and enantioenriched cyclopropanols and cyclopropylamines.