(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• . Bennet and co-workers also reported the synthesis of 1-amino-1,2-BCPs (±)-11a–e via a similar strategy (Scheme 1C) [29]. They were able to prepare differently-substituted [1.1.1]propellanes 3b–f and subject these to strain-release amination reactions. The synthesis was shown to tolerate typical alcohol

• [1.1.1]propellanes (Scheme 13B) [27]. These new syntheses increased the overall yield of the [3.1.1]propellane synthesis from Gassman’s original 6% to 23% (Uchiyama) and up to 35% (Anderson) in 5 steps. Iodine-substituted 1,5-BCHeps 134a–g were shown to be accessible from [3.1.1]propellane via

Design and synthesis of C₃-symmetric molecules bearing propellane moieties via cyclotrimerization and a ring-closing metathesis sequence

• Sambasivarao Kotha,
• Saidulu Todeti and
• Vikas R. Aswar

Beilstein J. Org. Chem. 2018, 14, 2537–2544, doi:10.3762/bjoc.14.230

• ; propellane; ring-closing metathesis; Introduction In 1966 Ginsburg coined the word “propellane” [1][2] and Wiberg reviewed various aspects of medium and small ring propellanes [3][4]. Propellanes consist of tricyclic compounds where three rings are conjoined by a common C–C bond [1][5][6]. Heterocyclic

• systems contain a heteroatom (e.g., oxygen, nitrogen, and sulfur, etc.) along with carbon atoms. The name of a heterocyclic propellane may be organized by prefixing aza, oxa, etc. Among various propellanes, nitrogen-containing compounds occupy a special place because they are present as core structural

• units in bioactive natural products and pharmaceuticals. Some of these propellanes exhibit intresting properties like antibiotic, antifungal, anticancer, platelet-activating factor antagonistic and antibacterial activities. The propellane skeleton is present in many alkaloids such as aknadinine (1

Bridgehead vicinal diallylation of norbornene derivatives and extension to propellane derivatives via ring-closing metathesis

• Sambasivarao Kotha and
• Rama Gunta

Beilstein J. Org. Chem. 2016, 12, 1877–1883, doi:10.3762/bjoc.12.177

• propellanes via ring-closing metathesis. Single-crystal X-ray diffraction analysis of four compounds led to the realization of configurational correction of earlier reported molecules. Keywords: norbornene; propellane derivatives; ring-closing metathesis; single-crystal X-ray diffraction; vicinal

Synthesis of indole-based propellane derivatives via Weiss–Cook condensation, Fischer indole cyclization, and ring-closing metathesis as key steps

• Sambasivarao Kotha,
• Ajay Kumar Chinnam and
• Arti Tiwari

Beilstein J. Org. Chem. 2013, 9, 2709–2714, doi:10.3762/bjoc.9.307

• propellane derivatives involves a Weiss–Cook condensation, a Fischer indole cyclization, and a ring-closing metathesis as key steps. Keywords: allylation; indole derivatives; propellanes; ring-closing metathesis; Weiss–Cook condensation; Introduction Propellanes are tricyclic systems conjoined with carbon

• –carbon single bonds (Figure 1) [1][2][3], and they are found to be highly congested. Some of these compounds are considered to be unstable entities and subjected to theoretical as well as synthetic studies [4]. Surprisingly, propellanes with larger rings, isolated from natural resources are found to be

• stable [5]. Among them, indole-based propellanes are useful in biology and medicine [6][7][8][9][10][11][12]. In 1963 Djerassi [13][14] isolated fendleridine and 1-acetylaspidoalbidine both of which belong to the aspidoalbine alkaloid family [15][16][17][18][19][20]. Kopsia alkaloids (Figure 2) show a

The arene–alkene photocycloaddition

• Ursula Streit and
• Christian G. Bochet

Beilstein J. Org. Chem. 2011, 7, 525–542, doi:10.3762/bjoc.7.61

• photocycloaddition followed by rearrangements. Stable [2 + 2] photocycloadducts. Ortho photocycloadditions with alkynes. Intramolecular ortho photocycloaddition and rearrangement thereof. Intramolecular ortho photocycloaddition to access propellanes. Para photocycloaddition with allene. Photocycloadditions of