- Enantioselective Halo-oxy- and Halo-azacyclizations Induced by Chiral Amidophosphate Catalysts and Halo-Lewis Acids
-
Catalytic enantioselective halocyclization of 2-alkenylphenols and enamides have been achieved through the use of chiral amidophosphate catalysts and halo-Lewis acids. Density functional theory calculations suggested that the Lewis basicity of the catalyst played an important role in the reactivity and enantioselectivity. The resulting chiral halogenated chromans can be transformed to α-Tocopherol, α-Tocotrienol, Daedalin A and Englitazone in short steps. Furthermore, a halogenated product with an unsaturated side chain may provide polycyclic adducts under radical cyclization conditions.
- Lu, Yanhui,Nakatsuji, Hidefumi,Okumura, Yukimasa,Yao, Lu,Ishihara, Kazuaki
-
supporting information
p. 6039 - 6043
(2018/05/14)
-
- Electrophilic Substitution of Hydrogen in Betulin and Diacetylbetulin
-
Betulin and diacetylbetulin, which can be regarded as sterically hindered alkenes, reacted with N-chloro-, N-bromo-, and N-iodosuccinimides to give products of allylic and vinylic substitution in quantitative overall yield. The contribution of allylic substitution increases in the series Cl Br I. Quantum chemical simulation of the reactions of diacetylbetulin with N-halosuccinimides showed that, regardless of the electrophile power, all reactions involve open-chain carbocationic intermediates. The direction of deprotonation of the latter with formation of allylic or vinylic substitution products is determined by preferential orientation of the vacant orbital and C–Hlg bond.
- Bodrikov,Kurskii, Yu. A.,Chiyanov,Subbotin, A. Yu.
-
p. 131 - 138
(2018/06/14)
-
- Pd-Catalyzed regioselective C-H halogenation of quinazolinones and benzoxazinones
-
A Pd-catalyzed ortho-selective halogenation of benzoxazinone and quinazolinone scaffolds has been described employing N-halosuccinimide as both a halogen source and an oxidant reagent via C-H bond activation. This transformation shows high chemo- and regioselectivities and demonstrates a broad range of benzoxazinone and quinazolinone substrates with different functional groups and has been scaled up to the gram level.
- Dabiri, Minoo,Farajinia Lehi, Noushin,Kazemi Movahed, Siyavash,Khavasi, Hamid Reza
-
supporting information
p. 6264 - 6268
(2017/08/02)
-
- Glycosylation with Disarmed Glycosyl Bromides Promoted by Iodonium Ions
-
Iodonium ions have been developed for activating glycosyl bromides in the coupling to glycosyl acceptors. The iodonium ions are generated from N-iodosuccinimide and a protic acid such as camphorsulfonic acid or triflic acid, where the latter gives the most reactive promoter system. The couplings occur with the release of iodine monobromide, and the best results are obtained with benzoylated glycosyl donors and acceptors. In this way, disarmed glycosyl bromides can serve as glycosyl donors without the use of heavy-metal salts.
- Lanz, Gyrithe,Madsen, Robert
-
supporting information
p. 3119 - 3125
(2016/07/12)
-
- Palladium-Catalyzed Carbamate-Directed Regioselective Halogenation: A Route to Halogenated Anilines
-
This study describes an efficient method for ortho-selective halogenation of N-arylcarbamates under mild conditions for the first time. Although being weakly coordinating, N-arylcarbamates act very well as a removable directing group for activation of C-H bonds. The developed procedure results in extremely valuable halogenated N-arylcarbmates that can further be hydrolyzed to halogenated anilines. The obtained reaction conditions showed broad scope and wide functional group tolerance. All the products were formed in good yields with extremely high selectivity.
- Moghaddam, Firouz Matloubi,Tavakoli, Ghazal,Saeednia, Borna,Langer, Peter,Jafari, Behzad
-
p. 3868 - 3876
(2016/05/24)
-
- PROCESS FOR THE PREPARATION OF N-IODOAMIDES
-
The present invention provides new stable crystalline N-iodoamides - 1-iodo- 3,5,5-trimethylhydantoin (1-ITMH) and 3-iodo-4,4-dimethyl-2-oxazolidinone (IDMO). The present invention further provides a process for the preparation of organic iodides using N-iodoamides of this invention and recovery of the amide co-products from waste water.
- -
-
Paragraph 00171-00172
(2015/05/26)
-
- Oxidative rearrangement of Indoles: A new approach to the EFHG-tetracyclic core of diazonamide A
-
(Chemical Equation Presented) A new approach to the ring EFHG-tetracyclic core fragment of the marine secondary metabolite diazonamide A is described. The route is based on the oxidative rearrangement of 3-arylindole-2-carboxylates. Thus, a range of 3-arylindole-2-carboxylates (3, 8) underwent rearrangement to the corresponding 3,3-disubstituted oxindoles (4, 9) with migration of the ester group upon treatment with tert-butyl hypochlorite followed by acid. The oxindoles 9 with a 3-[2-(4-methoxybenzyloxy)]phenyl substituent underwent cyclization to the tetracyclic aminals 11 following N-protection, reduction, and treatment with methanesulfonic anhydride. The methodology was applied to the tyrosine-indole derivative 17 to give the EFHG-tetracyclic core of diazonamide A.
- Poriel, Cyril,Lachia, Mathilde,Wilson, Claire,Davies, James R.,Moody, Christopher J.
-
p. 2978 - 2987
(2008/02/01)
-
- 2-Substituted 5-amino-3-oxo-4-(substituted-phenyl)-2,3-dihydrofuran herbicides
-
2-Halo and 2-alkoxy-5-amino-3-oxo-4-(substituted-phenyl)-2,3-dihydrofuran and derivatives thereof. The 2-alkoxy and 2-fluoro compounds generally exhibit both pre-emergence and post-emergence phytotoxicity and are useful as herbicides and also at low dosages as plant growth regulating agents. The 2-bromo, chloro and iodo compounds are primarily useful as intermediates for the 2-alkoxy and 2-fluoro analogs.
- -
-
-
- N-CHLOROSUCCINIMIDE/SODIUM IODIDE: A CONVENIENT SOURCE OF N-IODOSUCCINIMIDE. SYNTHESIS OF α-IODO CARBONYL COMPOUNDS AND TRANS-1,2-IODOACETATES
-
Equimolar amounts of N-chlorosuccinimide and sodium iodide in acetone are found to be a convenient source of N-iodosuccinimide using which trans-1,2-iodoacetates and α-iodo carbonyl compounds have been prepared from olefins and enol silyl ethers respectively.
- Vankar, Yashwant D.,Kumaravel, G.
-
p. 233 - 236
(2007/10/02)
-
- E-5-(2-Halogenovinyl)-2'-deoxycytidines
-
The invention relates to E-5-(2-halogenovinyl)-2'-deoxycytidines, e.g. E-5-(bromovinyl)-2'-deoxycytidine and E-5-(2-iodovinyl)-2'-deoxycytidine. These substances are endowed with specific antiviral activities towards herpes simplex virus and with an extremely low toxicity which makes them useful in antiviral medicines and for treatment of virus diseases in man and animal. They may be synthesized by introduction of an E-5-(2-halogenovinyl) sidechain into 2'-deoxycytidine, or by condensation of a trialkylsilyl derivative of E-5-(2-halogenovinyl)-cytosine with a hydroxyl-protected reactive derivative of 2'-deoxy-D-erythro-pentofuranose.
- -
-
-
- TIN(IV) MEDIATED SYNTHESIS OF N-HALO COMPOUNDS
-
Some representative N-halo compounds like N-bromosuccinimide, N-iodosuccinimide, N-bromophthalimide, N-iodophthalimide, N-iodobenzimidazole and N-iodobenzotriazole have been synthesised in good yields under neutral and mild conditions via an intermediate formed from the parent NH species and bis(tri-n-butyltin) oxide.The tin oxide is recovered as recyclable tri-n-butyltin halide.
- Soundararajan, R.,Krishnamurthy, S.,Srinivasan, Vilanoor S.,Balasubramanian, T.R.
-
p. 295 - 298
(2007/10/02)
-
