Cp₂TiCl/D₂O/Mn, a formidable reagent for the deuteration of organic compounds

• Antonio Rosales and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2016, 12, 1585–1589, doi:10.3762/bjoc.12.154

• experimental conditions and with great economic advantages. Keywords: deuteration; deuterium atom transfer; radical and/or organometallic chemistry; titanocene; Introduction Deuterium is a stable isotope of hydrogen with 0.015% natural abundance broadly used in organic chemistry, pharmacology, organometallic

• -ordination of water to Cp2TiCl might weakens the strength of the O–H bond. In this way a single electron transfer from titanium to oxygen might facilitate the HAT from the titanocene aqua-complex to the free radicals. Theoretical calculations supported that the coordination of water to Cp2TiIIICl weakens the

Attempts to prepare an all-carbon indigoid system

• Şeref Yildizhan,
• Henning Hopf and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 363–372, doi:10.3762/bjoc.11.42

• with Oshima–Lombardo reagent (Zn, CH2Br2, TiCl4) [20][21] yielded a trace of 4. Likewise, the exposure of 21 to Tebbe’s reagent (trimethylaluminum with titanocene dichloride, pyridine, toluene) led to no sign of reaction in the desired sense. Nor was the tetramethyl derivative of 4, hydrocarbon 14

Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

• Andreas Gansäuer,
• Andreas Okkel,
• Lukas Schwach,
• Laura Wagner,
• Anja Selig and
• Aram Prokop

Beilstein J. Org. Chem. 2014, 10, 1630–1637, doi:10.3762/bjoc.10.169

• ’ functionalized titanocene building blocks for further synthetic elaboration. Our synthesis is modular and large numbers of the complexes can in principle be prepared in short periods of time. Some of the triazole-substituted titanocenes display high cyctotoxic activity against BJAB cells. Comparison of the most

• functional groups is difficult due to the nucleophilicity of the cyclopentadienyl anions before metalation and the electrophilicity of titanium after metalation [21][22]. We have devised a conceptually different approach addressing these issues. It relies on the use of carboxylate-containing titanocene

• functions. An especially attractive approach is the use of already functionalized building blocks as starting materials in diversity oriented synthesis that increases the molecular complexity. Any synthetic methodology used in this context must take into account the sensitivity of the titanocene towards

Computational study of the rate constants and free energies of intramolecular radical addition to substituted anilines

• Andreas Gansäuer,
• Meriam Seddiqzai,
• Tobias Dahmen,
• Rebecca Sure and
• Stefan Grimme

Beilstein J. Org. Chem. 2013, 9, 1620–1629, doi:10.3762/bjoc.9.185

• the addition is about as fast as the 6-endo cyclization of the hexenyl radical. Such reactions and other even slower cyclizations are well documented in titanocene mediated and catalyzed radical processes [61][62][63][64][65][66][67][68][69]. Therefore, the relatively high computational rate constant

• and an electrophilic radical center is disadvantageous. This is in agreement with preliminary synthetic results that suggest that dihydrobenzofurans and indanes are not accessible via the titanocene catalyzed radical arylation. Conclusion The intramolecular radical addition to substituted anilines was

Recent advances in transition-metal-catalyzed intermolecular carbomagnesiation and carbozincation

• Kei Murakami and
• Hideki Yorimitsu

Beilstein J. Org. Chem. 2013, 9, 278–302, doi:10.3762/bjoc.9.34

• intermediate to provide the corresponding alkylmagnesium compounds 4j, which could be employed for further reactions with various electrophiles (Scheme 42). In 2004, Kambe reported titanocene-catalyzed carbomagnesiation, which proceeded through radical intermediates not metallacyclopropanes (Scheme 43) [131

• ]. As a result, Hoveyda’s zirconium-catalyzed reactions provided homobenzylmagnesium intermediates 4j, while Kambe’s titanium-catalyzed reactions afforded benzylmagnesium intermediates 4k. Kambe applied the titanocene-catalyzed reaction to a three-component coupling reaction involving a radical

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

• of other arylated bisallenes and presumably takes place via radical intermediates. A more recent way to allenes exploits the allenation of carbonyl compounds with titanocene alkenylidene reagents such as 60. When applied to bibenzoyl (benzil), 61, the 3,4-diphenylhexatetraene 62 is produced in good

Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

• Lukas Hintermann,
• Mauro Perseghini and
• Antonio Togni

Beilstein J. Org. Chem. 2011, 7, 1421–1435, doi:10.3762/bjoc.7.166

• enantiopure sample of the ansa-titanocene [(EBTHI)Ti(OTf)2] (Figure 4) [79][80][81] indeed catalyzed the slow fluorination of 1 (14% conversion after 18 h, 25% after 36 h, 30 d to completion) or 2 (85% conversion after 18 h), but gave racemic products 1-F and 2-F. Dialkoxyaluminium chlorides, which were