- Difunctionalization of Alkenes Using 1-Chloro-1,2-benziodoxol-3-(1H)-one
-
Difunctionalization of alkenes with 1-chloro-1,2-benziodoxol-3-(1H)-one (1) was investigated. Various additional nucleophiles were tested, and oxychlorination, dichlorination, azidochlorination, chlorothiocyanation, and iodoesterfication were demonstrated. The oxychlorination product was obtained efficiently when the reaction was operated in water. Dichlorination occurred in the presence of a Lewis basic promoter, such as 4-phenylpyridine N-oxide, as an additive. The reaction with in situ-generated azido anion afforded azidochlorinated compounds with a chlorine atom at the terminal position, while the reaction with trimethylsilyl isothiocyanate produced chlorothiocyanation adducts with a chlorine atom at the benzylic position. On the other hand, when 1 was treated with tetra-n-butylammonium iodide prior to the addition of alkenes, only iodoesterification occurred selectively. These mild reactions enable convenient site-selective difunctionalizations of substrates having two alkene moieties. NMR experiments suggested that the electrophilic reactive species in each reaction varied depending on the nature of the added nucleophile.
- Egami, Hiromichi,Yoneda, Takahiro,Uku, Minako,Ide, Takafumi,Kawato, Yuji,Hamashima, Yoshitaka
-
p. 4020 - 4030
(2016/06/09)
-
- Taming chlorine azide: Access to 1,2-azidochlorides from alkenes
-
The in situ preparation and trapping of chlorine azide provided a versatile one-pot method for the azidochlorination of alkenes. Gaseous ClN3 generated from sodium azide, hypochlorite, and acetic acid can be explosive if isolation is attempted. Instead, we generated the reagent in biphasic media in the presence of olefinic compounds dissolved in the organic layer or evenly emulsified throughout the solution in the absence of organic solvent. Under these conditions, ClN3 is created slowly and trapped immediately at the aqueous-organic interface. The resulting safe and reliable procedure provided 1,2-azidochloride derivatives of a variety of substrates, with evidence for both polar and radical mechanisms. Minor impurities characterized in the product mixtures indicated the presence of alternative reaction pathways deriving primarily from radical intermediates.
- Valiulin, Roman A.,Mamidyala, Sreeman,Finn
-
supporting information
p. 2740 - 2755
(2015/03/18)
-
- The vicinal functionalization of olefins: A facile route to the direct synthesis of β-chlorohydrins and β-chloroethers
-
An efficient and environmentally benign protocol for the synthesis of vicinal chlorohydroxy and chloromethoxy derivatives in a highly regioselective manner from olefins using NH4Cl as a chlorine source and oxone as an oxidant in aqueous acetone and methanol is demonstrated. This methodology offers an additive and metal chloride free approach and is endowed with simple reaction conditions, high yields a broad substrate scope and good functional group tolerance. Moreover, the aromatic substrates with a terminal double bond exhibited merely Markovnikov selectivity, while the internal alkenes show exclusive regiocontrol and low to moderate diastereoselectivity.
- Swamy, Peraka,Kumar, Macharla Arun,Reddy, Marri Mahender,Naresh, Mameda,Srujana, Kodumuri,Narender, Nama
-
p. 26288 - 26294
(2014/07/08)
-
- Highly regio- and diastereoselective halohydroxylation of olefins: A facile synthesis of vicinal halohydrins
-
An efficient method for the synthesis of vicinal chlorohydrin or bromohydrin derivatives has been developed on the basis of direct halohydroxylation of various olefins with electrondonating or withdrawing substituent. The reactions were carried out under mild conditions in the presence of N-tosyl-l-threonine (NTsLT) as an acidic additive using chloramine T trihydrate, 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) or N-bromoacetamide (AcNHBr) as the halogen source, respectively, affording the corresponding vicinal halohydrins in good to high yields with excellent regio- and stereoselectivities.
- Zhang, Jinglei,Wang, Jie,Qiu, Zhuibai,Wang, Yang
-
experimental part
p. 6859 - 6867
(2011/10/02)
-
- Dynamic kinetic resolution of racemic β-haloalcohols: Direct access to enantioenriched epoxides
-
The direct chemo-enzymatic DKR of racemic β-haloalcohols is reported, yielding the corresponding optically active epoxides in a single step. The mutant haloalcohol dehalogenase HheC Cys153Ser Trp249Phe is used for the asymmetric ring closure, whereas racemization of the remaining enantiomer of the haloalcohol is achieved using the new iridacycle 3, one of the most effective racemization catalysts to date for β-haloalcohols. Copyright
- Haak, Robert M.,Berthiol, Florian,Jerphagnon, Thomas,Gayet, Arnaud J. A.,Tarabiono, Chiara,Postema, Christiaan P.,Ritleng, Vincent,Pfeffer, Michel,Janssen, Dick B.,Minnaard, Adriaan J.,Feringa, Ben L.,De Vries, Johannes G.
-
supporting information; body text
p. 13508 - 13509
(2009/02/06)
-
- Process for the preparation of tricyclic amino alcohol derivatives
-
A process for the preparation of tricyclic amino alcohol derivatives including 2-[N-[2-(9H-carbazol-2-yloxy)ethyl]]amino-1-[(3-methylsulfonylamino)phenyl]ethanol useful in the treatment of diabetes, obesity, hyperlipidemia and so on; and intermediates as represented by formula (5) or (6) or the like useful in the preparation, wherein R11 is hydrogen or the like; and *1 represents an asymmetric carbon atom. 2-Halo-1-(3-nitrophenyl)ethanone derivatives and 1-(3-nitrophenyl)oxirane derivatives, which are intermediates for the preparation of tricyclic amino alcohol derivatives, are easy of purification, and particularly optically active 1-(3-nitrophenyl)oxirane derivatives are effective in enhancing the optical purities of the final products.
- -
-
-