Journal ArticleDOI
Photochemical Pinacol Rearrangement
Mary Hoang,Timothy A. Gadosy,Hedieh Ghazi,Dong-Feng Hou,Alan C. Hopkinson,Linda J. Johnston,Edward Lee-Ruff +6 more
Reads0
Chats0
TLDR
Comparison of the decay kinetics between cation 5 and other 9-fluorenyl cations showed that the decay of 5 was relatively insensitive to the nature of the solvent as compared to the latter two carbocations suggesting that unimolecular rearrangement in 5 competes with nucleophilic quenching.Abstract:
Irradiation of 9,9‘-bifluorene-9,9‘-diol (1) gave 9-fluorenone and spiro[9H-fluorene-9,9‘(10‘-H)-phenanthren]-10‘-one (4), the latter arising from a pinacol rearrangement. The distribution of fluorenone and ketone 4 was solvent dependent with the latter being the major product in trifluoroethanol, a solvent known to stabilize carbocation intermediates. Laser flash photolysis of diol 1 in 2,2,2-trifluoroethanol or hexafluoro-2-propanol showed two transients absorbing at 350 and 505 nm with a weak band at 700 nm. The latter two peaks are assigned to the corresponding substituted 9-fluorenyl cation (5) formed from photoheterolysis of diol 1. Comparison of the decay kinetics between cation 5 and other 9-fluorenyl cations, the parent 9-fluorenyl and 9-phenyl-9-fluorenyl cations, showed that the decay of 5 was relatively insensitive to the nature of the solvent as compared to the latter two carbocations suggesting that unimolecular rearrangement in 5 competes with nucleophilic quenching.read more
Citations
More filters
Journal ArticleDOI
A pinacol rearrangement/oxidation synthetic route to hydroxyphenstatin.
TL;DR: Benzophenone 2b, designated hydroxyphenstatin, a potent antitumor and antimitotic agent, showed potent inhibition of the tubulin assembly and exhibited an ED(50) of 2.5 microg/mL against the P388 lymphocytic leukemia cell line.
Journal ArticleDOI
Studies of 9-fluorenyl carbocations. intramolecular hydride migration in a substituted 9-fluorenyl carbocation.
Gabriela Mladenova,L Chen,Christopher F. Rodriquez,K W Siu,Linda J. Johnston,Alan C. Hopkinson,Edward Lee-Ruff +6 more
TL;DR: Iradiation of 9-(diphenylmethyl)fluoren-9-ol in methanol gives products derived from the corresponding cation along with radical-derived products from C-C and C-O homolysis processes.
Journal ArticleDOI
Direct transformation of silyl enol ethers into functionalized allenes.
TL;DR: The first elimination reactions of silyl enol ethers to lithiated allenes are reported, which allow a direct transformation of readily available sily l enl ethers into functionalized allenes.
Journal ArticleDOI
Hexabenzo[4.4.4]propellane: a helical molecular platform for the construction of electroactive materials.
TL;DR: Isolation and X-ray crystallographic characterization of a robust trication-radical salt of hexamethoxypropellane derivative confirms that its framework is stable toward oxidative (aliphatic) C-C bond cleavage.
Journal ArticleDOI
Synthesis and domino reactions of 1,1-bis(hydroxymethyl)allenes
TL;DR: The reaction of dilithiated 1,1-diphenylallene with aryl ketones provides a convenient access to novel 1, 1-bis(hydroxymethyl)allenes, which undergo Friedel-Crafts-type domino reactions upon treatment with TsOH as mentioned in this paper.
References
More filters
Journal ArticleDOI
Pulse radiolysis study of aqueous nitric acid solutions: formation mechanism, yield, and reactivity of NO3 radical
TL;DR: In this paper, a pulse radiolysis study of aqueous nitric acid and nitrate solutions has been carried out, and the formation kinetics of NO{sub 3} radical was followed with nanosecond time resolution.
Journal ArticleDOI
Laser flash photolysis of 9-fluorenol. Production and reactivities of the 9-fluorenol radical cation and the 9-fluorenyl cation
Journal ArticleDOI
Enantiospecific total synthesis of pseudopterosins A and E
E. J. Corey,Philip Carpino +1 more
TL;DR: Preparation de ces composes a partir d'une oxime de cyclohexyl-2 propanal et d'un O-benzyl 2 fucose pour la pseudopterosine E ou d'unes bromure de xylopyranosyle.