A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

Photocatalysis with organic dyes: facile access to reactive intermediates for synthesis

• Stephanie G. E. Amos,
• Marion Garreau,
• Luca Buzzetti and
• Jerome Waser

Beilstein J. Org. Chem. 2020, 16, 1163–1187, doi:10.3762/bjoc.16.103

• opening of nitrogen-containing small rings was also exploited by our group in 2019 (Scheme 36) [154]. Starting from the aminocyclopropanes 36.1 and the cyclopropenes 36.2, a [3 + 2] annulation led to the bicyclo[3.1.0]hexanes 36.3. Under visible-light irradiation, the excited-state photocatalyst OD7

One-pot sequential synthesis of tetrasubstituted thiophenes via sulfur ylide-like intermediates

• Jun Ki Kim,
• Hwan Jung Lim,
• Kyung Chae Jeong and
• Seong Jun Park

Beilstein J. Org. Chem. 2018, 14, 243–252, doi:10.3762/bjoc.14.16

• center and the substituents on the sulfur atom [10]. In general, these reagents are often applied in the preparation of simple small rings [13], such as epoxides [14][15][16][17][18], cyclopropanes [19][20][21][22], aziridines [23], indoles [24], pyrroles [24], and indolines [25]. In addition, other

Are boat transition states likely to occur in Cope rearrangements? A DFT study of the biogenesis of germacranes

• José Enrique Barquera-Lozada and
• Gabriel Cuevas

Beilstein J. Org. Chem. 2017, 13, 1969–1976, doi:10.3762/bjoc.13.192

• , since in this case the elemanolide is more stable than the (Z,E)-germacranolide. Contrary to what other authors have proposed, the inability of (Z,E)-germacranes to transform into elemanes via a Cope rearrangement when (Z,E)-germacranes have small rings (lactone) fused is not due to an increase of the

• activation energy of the Cope rearrangement. The activation energy does not change significantly when the fused ring is open or closed, but when the ring is open, the elemane is more stable. A fused small ring produces a lot of strain in the elemanes. In summary, fused small rings increase significantly the

Recent applications of ring-rearrangement metathesis in organic synthesis

• Sambasivarao Kotha,
• Milind Meshram,
• Priti Khedkar,
• Shaibal Banerjee and
• Deepak Deodhar

Beilstein J. Org. Chem. 2015, 11, 1833–1864, doi:10.3762/bjoc.11.199

• metathesis (RCEM) of small-rings such as cyclopropenes by employing the Grubbs’ first-generation (G-I) catalyst. They have reported a new tandem ROM–RCM–CM sequence starting with 1,6-cyclopropenynes 16 with a wide variety of substituted olefins. To this end, the required building block 16 has been prepared

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• or alkenes bearing no hydrogen on the double bond. Additionally, due to the absence of small rings containing a triple bond, no cyclic alkenylphosphines are accessible. Until now, the protocols lack sufficient control over selectivity and mostly give mixtures. Most addition products (radical, base

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• groups are tolerated in the IMCRs [19]. In this overview we focus on all recent developments in the last decade in the field of cyclic peptidomimetics obtained from IMCRs and their subsequent cyclization reactions. The cyclic mimics herein range from small rings (four to seven membered), medium sized

• ]. Review Small ring constraints In the first part of this review four- to seven-membered cyclic peptidomimetics will be discussed. These small rings, particularly heterocycles, have received much attention as dipeptide mimics due to their capable interaction with defined protein motifs and due to their

Gold-catalyzed reaction of oxabicyclic alkenes with electron-deficient terminal alkynes to produce acrylate derivatives

• Yin-wei Sun,
• Qin Xu and
• Min Shi

Beilstein J. Org. Chem. 2013, 9, 1969–1976, doi:10.3762/bjoc.9.233

• interest in gold-catalyzed C–C [57][58][59][60][61] or C–X bond [62][63][64][65][66][67] formation reactions. So far, we have reported a variety of gold-catalyzed intramolecular rearrangements with highly strained small rings for C–C or C–X bond formations [57][58][59][62][63][64][65][66][67][68]. Based on

Chemistry of polyhalogenated nitrobutadienes, 10: Synthesis of highly functionalized heterocycles with a rigid 6-amino-3-azabicyclo[3.1.0]hexane moiety

• Viktor A. Zapol’skii,
• Jan C. Namyslo,
• Armin de Meijere and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2012, 8, 621–628, doi:10.3762/bjoc.8.69

• feasible. Keywords: isothiazole; nitrochlorobutadiene; nitropyrazole; nucleophilic substitution; pyrimidine; small rings; Introduction Nitropolychlorobutadienes are potent precursors for a variety of highly functionalized acyclic and (hetero)cyclic compounds. The readily accessible 2-nitroperchloro-1,3