Ti-Catalyzed Homolytic Opening of Ozonides: A Sustainable C–C Bond-Forming Reaction

Rosales, Antonio; Muñoz-Bascón, Juan; López-Sánchez, Cristóbal; Álvarez-Corral, Míriam; Muñoz‐Dorado, Manuel; Rodrı́guez-Garcı́a, Ignacio; Oltra, J. Enrique

doi:10.1021/jo300344a

Cited by 36 publications

(33 citation statements)

References 32 publications

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“…Reaction of 13 with TCDI (thiocarbonyl diimidazole) and DMAP gave thiocarbamate 14 . Our first attempts to get rid of the thiocarbamate moiety using standard Barton–McCombie conditions9a–9c were disappointing, and gave yields around 40 %. Optimization of the reaction conditions (e.g., temperature, concentration, stoichiometry) resulted in the formation of the desired (+)‐albicanyl acetate ( 15 ) in very good yields.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol

Göhl

Seifert

2014

Eur J Org Chem

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A TiIII‐mediated radical cyclization cascade has been used for the synthesis of the sesquiterpenes (+)‐albicanol, (+)‐drimanol, and (+)‐drimanic acid. Starting from all‐trans‐farnesol, (+)‐albicanol could be prepared in seven steps in an overall yield of 14.9 %. Furthermore, a highly diastereoselective hydrogenation of (+)‐albicanol to give (+)‐drimanol has been developed. We used the synthesized (+)‐drimanic acid to achieve the first synthesis of the marine sesquiterpene hydroquinone deoxyspongiaquinol and the quinone deoxyspongiaquinone. Thus, this synthetic strategy gave access to five natural products.

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Section: Resultsmentioning

confidence: 99%

Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol

Göhl

Seifert

2014

Eur J Org Chem

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“…The product was collected via filtration, washed with small amounts of water and diethyl ether, and dried under reduced pressure to give [(C 6 F 5 OOC-tpy)Ru(tpy-NHCOCH 3 24.0 (s, NHCOCH 3 ), (carbon signals of C 6 F 5 not observed). 74 19 Synthesis of 3(PF 6 ) 4 . [(C 6 F 5 OOC-tpy)Ru(tpy-NHCOCH 3 )](PF 6 ) 2 7(PF 6 ) 2 (59.5 mg, 0.053 mmol) and [(EtOOC-tpy)Ru(tpy-NH 2 )]-(PF 6 ) 2 5(PF 6 ) 2 (50 mg, 0.053 mmol) were each dissolved separately in acetonitrile (10 mL) under an atmosphere of argon and left to stand overnight over activated molecular sieves (3 Å) to remove crystal water.…”

Section: ■ Introductionmentioning

confidence: 99%

Dual Emission and Excited-State Mixed-Valence in a Quasi-Symmetric Dinuclear Ru–Ru Complex

et al. 2014

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The synthesis and characterization of the new dinuclear dipeptide [(EtOOC-tpy)Ru(tpy-NHCO-tpy)Ru(tpy-NHCOCH3)](4+) 3(4+) of the bis(terpyridine)ruthenium amino acid [(HOOC-tpy)Ru(tpy-NH2)](2+) 1(2+) are described, and the properties of the dipeptide are compared to those of the mononuclear complex [(EtOOC-tpy)Ru(tpy-NHCOCH3)](2+) 4(2+) carrying the same functional groups. 3(4+) is designed to serve a high electronic similarity of the two ruthenium sites despite the intrinsic asymmetry arising from the amide bridge. This is confirmed via UV-vis absorption and NMR spectroscopy as well as cyclic voltammetry. 4(2+) and 3(4+) are emissive at room temperature, as expected. Moreover, 3(4+) exhibits dual emission from two different triplet states with different energies and lifetimes at room temperature. This is ascribed to the presence of a unique thermal equilibrium between coexisting [Ru(II)(tpy-NHCO-tpy(·-))Ru(III)] and [Ru(III)(tpy-NHCO-tpy(·-))Ru(II)] states leading to an unprecedented excited-state Ru(II)Ru(III) mixed-valent system via the radical anion bridge tpy-NHCO-tpy(·-). The mixed-valent cation 3(5+), on the other hand, shows no measurable interaction of the Ru(II)Ru(III) centers via the neutral bridge tpy-NHCO-tpy (Robin-Day class I). Reduction of 3(4+) to the radical cation 3(3+) by decamethylcobaltocene is bridge-centered as evidenced by rapid-freeze electron paramagnetic resonance spectroscopy. Interestingly, all attempts to observe 3(3+) via NMR and UV-vis absorption spectroscopy only led to the detection of the diamagnetic complex 3-H(3+) in which the bridging amide is deprotonated. Hence 3-H(3+) (and 4-H(+)) appear to reduce protons to dihydrogen. The ease of single and double deprotonation of 4(2+) and 3(4+) to 4-H(+), 3-H(3+), and 3-2H(2+) was demonstrated using a strong base and was studied using NMR and UV-vis absorption spectroscopies. The equilibrating excited triplet states of 3(4+) are reductively quenched by N,N-dimethylaniline assisted by hydrogen bonding to the bridging amide.

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“…This SET is capable of promoting and/or catalyzing several transformations in organic chemistry [ 17 – 25 ]. One of the most relevant transformations is the H/D-atom transfer from H 2 O/D 2 O to carbon radicals (pathway A) (obtained from epoxides [ 26 – 28 ], ozonides [ 29 ] or activated halides [ 30 ] and Cp 2 TiCl/Mn), to intermediate titanaoxiranes (pathway B) [ 31 – 32 ] (obtained from carbonyl compounds and Cp 2 TiCl/Mn), and to late transition metals (pathway C) [ 33 ] in a process mediated by Cp 2 TiCl/Mn/H 2 O or D 2 O which allows for the reduction of alkenes or alkynes ( Scheme 1 ).…”

Section: Discussionmentioning

confidence: 99%

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

Rosales¹,

Rodrı́guez-Garcı́a²

2016

Beilstein J. Org. Chem.

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Ti-Catalyzed Homolytic Opening of Ozonides: A Sustainable C–C Bond-Forming Reaction

Cited by 36 publications

References 32 publications

Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol

Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol

Dual Emission and Excited-State Mixed-Valence in a Quasi-Symmetric Dinuclear Ru–Ru Complex

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

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Ti-Catalyzed Homolytic Opening of Ozonides: A Sustainable C–C Bond-Forming Reaction

Cited by 36 publications

References 32 publications

Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol

Synthesis of the Sesquiterpenes Albicanol, Drimanol, and Drimanic Acid, and the Marine Sesquiterpene Hydroquinone Deoxyspongiaquinol

Dual Emission and Excited-State Mixed-Valence in a Quasi-Symmetric Dinuclear Ru–Ru Complex

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

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