Synthesis of disparlure and monachalure enantiomers from 2,3-butanediacetals

• Adam Drop,
• Hubert Wojtasek and
• Bożena Frąckowiak-Wojtasek

Beilstein J. Org. Chem. 2020, 16, 616–620, doi:10.3762/bjoc.16.57

• isomerization of trans-2,3-butanediacetals to the cis-isomers has also been performed via dithiolate derivative 10 to obtain compound 13 (Scheme 2) [35]. However, attempts to isomerize dimethyl ester 9 in the same way gave a cyclic compound as a major product [36]. We have recently developed a simple and

Synthesis of six-membered silacycles by borane-catalyzed double sila-Friedel–Crafts reaction

• Yafang Dong,
• Masahiko Sakai,
• Kazuto Fuji,
• Kohei Sekine and
• Yoichiro Kuninobu

Beilstein J. Org. Chem. 2020, 16, 409–414, doi:10.3762/bjoc.16.39

• been demonstrated. Keywords: borane; cyclic compound; organosilane; sila-Friedel–Crafts; silylation; Introduction Six-membered silacyclic compounds, such as phenoxasilin and phenothiasilin derivatives, are attractive compounds for applications as organic electronic materials [1][2][3][4], ligands [5

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• from α-C–H bond activation in heterocycles The α-position to a heteroatom in a cyclic compound is activated because of the difference in electronegativity with carbon. This presents an opportunity to readily generate organometallic nucleophiles. Chelucci et al. [71] used this fact to synthesize the

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• /cyclisation processes, as demonstrated by Miyabe and co-workers [27]. Thus, in typical photoredox catalysis conditions, N-allyl-N-(benzyloxy)methacrylamide 23 could undergo the addition of the CF3 radical, followed by a cyclisation step and a final chlorine abstraction to yield the corresponding cyclic

• compound, albeit in low yield and with poor regio- and diastereoselectivity (Scheme 19). Interestingly, the authors proposed a mechanism involving a chain propagation pathway, in contrast to the work of Jung and Han. A similar cascade reaction was also performed on diethyl 2-allyl-2-(3-methylbut-2-en-1-yl

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• succinoyl group at C-2 was coupled to the diol galactosyl acceptor 6 in the presence of DCC and DMAP. The resulting tether compound 7 was obtained in 63% yield. The intramolecular glycosylation of the latter gave cyclic compound 8 in 76% yield, which was sequentially deacylated and per-benzoylated to afford

• 27 using tin-mediated primary alkylation to afford the tethered pair 28. The latter is then intramolecularly glycosylated in the presence of NIS/TfOH in 93% yield and complete stereoselectivity. The resulting cyclic compound 29 is then subjected to concomitant xylylene tether removal and

Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

• Maximilian Maier,
• Magnus S. Schmidt,
• Markus Ringwald and
• Christoph P. Fik

Beilstein J. Org. Chem. 2017, 13, 372–383, doi:10.3762/bjoc.13.40

• ) was synthesized from cis-but-2-ene-1,4-diol (17) using two different pathways; both reactions resulted in poor yields and product quality. Unfortunately, the reaction of 18 with allylamine did not result in the formation of 19, but to the undesired cyclic compound 20. The formation of the latter

Determination of the absolute stereostructure of a cyclic azobenzene from the crystal structure of the precursor containing a heavy element

• Reji Thomas and
• Nobuyuki Tamaoki

Beilstein J. Org. Chem. 2016, 12, 2211–2215, doi:10.3762/bjoc.12.212

• ; cyclic compound; enantiomer; stereostructure; X-ray crystal analysis; Introduction Chirality is a topic of fundamental importance in several branches of science [1][2][3][4][5]. Homochirality in nature was one of the most important challenges for researchers and the origin is still unsolved [6][7][8

Biosynthesis of oxygen and nitrogen-containing heterocycles in polyketides

• Franziska Hemmerling and
• Frank Hahn

Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148

• cyclic compound 72 (Scheme 11b) [56]. This result has been confirmed by in vivo experiments of Shen et al. [59]. NonS was annotated as an enoyl-CoA hydratase and shows a high degree of up to complete identity amino acid homology to mostly uncharacterised enzymes in several other clusters of Streptomyces

Synthesis of cyclic N¹-pentylinosine phosphate, a new structurally reduced cADPR analogue with calcium-mobilizing activity on PC12 cells

• Ahmed Mahal,
• Stefano D’Errico,
• Nicola Borbone,
• Brunella Pinto,
• Agnese Secondo,
• Valeria Costantino,
• Valentina Tedeschi,
• Giorgia Oliviero,
• Vincenzo Piccialli and
• Gennaro Piccialli

Beilstein J. Org. Chem. 2015, 11, 2689–2695, doi:10.3762/bjoc.11.289

• regioisomer 7 equipped with the reactive phosphorous(III) group. Unfortunately, the activation of the phosphoramidite function with 1H-tetrazole aimed at inducing the cyclization on the 5’-OH ribose function produced only a complex mixture. No traces of the target cyclic compound were detected after the usual

• reaction allowed to stand at room temperature for 48 h. From this mixture it was possible to isolate cyclic compound 19 (30% cyclization yield) whose structure was confirmed by NMR and high-resolution mass analyses. Eventually, the treatment of compound 19 with aqueous 20% TFA afforded the target compound

Gold(I)-catalyzed synthesis of γ-vinylbutyrolactones by intramolecular oxaallylic alkylation with alcohols

• Michel Chiarucci,
• Mirko Locritani,
• Gianpiero Cera and
• Marco Bandini

Beilstein J. Org. Chem. 2011, 7, 1198–1204, doi:10.3762/bjoc.7.139

• acids (BA) was verified by means of experimental controls with TsOH (entry 15), and also in the presence of an acid scavenger (entry 16). Here, the desired cyclic compound 2a was obtained in lower yield (64%) with concomitant substantial decomposition of the starting allylic alcohol. Such evidence

Efficient gold(I)/silver(I)-cocatalyzed cascade intermolecular N-Michael addition/intramolecular hydroalkylation of unactivated alkenes with α-ketones

• Ya-Ping Xiao,
• Xin-Yuan Liu and
• Chi-Ming Che

Beilstein J. Org. Chem. 2011, 7, 1100–1107, doi:10.3762/bjoc.7.126

• -ketone intermediate I and subsequent gold(I)-catalyzed intramolecular hydroalkylation of the α-ketone intermediate I to form the cyclic compound 3 (Scheme 3). Conclusion In summary, we have developed a simple and efficient gold(I)/silver(I)-cocatalyzed cascade intermolecular N-Michael addition

Recent advances in the gold-catalyzed additions to C–C multiple bonds

• He Huang,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103

• triple bond formed the vinyl–gold complex. Surprisingly, no other cyclic compound formed by nucleophilic attack of the hydroxy oxygen atom on C-6-position to a gold-coordinated C–C triple bond was formed. A new efficient route to furans 11 by gold-catalyzed intramolecular nucleophilic attack of readily

Synthesis of some novel annulated pyrido[2,3-d]pyrimidines via stereoselective intramolecular hetero Diels–Alder reactions of 1-oxa-1,3-butadienes

• Mohit L. Deb and
• Pulak J. Bhuyan

Beilstein J. Org. Chem. 2010, 6, No. 11, doi:10.3762/bjoc.6.11

• of the reactions the cis-annelated products were formed either predominantly or exclusively. As the oxabutadiene is part of a cyclic compound and two carbon atoms to which the dienophile is attached are part of a ring system, the endo-transition state is energetically more favorable than the exo