- Regiodivergent Conversion of Alkenes to Branched or Linear Alkylpyridines
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Herein we report a practical protocol for the visible-light-induced regiodivergent radical hydropyridylation of unactivated alkenes using pyridinium salts. This approach provides a unified synthetic platform to control the regioselectivity of the synthesis of linear or branched C4-alkylated pyridines. A remarkable selectivity switch from the anti-Markovnikov to the Markovnikov product can be achieved by the addition of tetrabutylammonium bromide. The versatility of this protocol is further demonstrated based on the late-stage functionalization in pharmaceuticals.
- Hong, Sungwoo,Jung, Sungwoo,Kim, Minseok,Koo, Yejin,Shin, Sanghoon
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supporting information
(2022/01/20)
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- Site-selective aliphatic C-H bromination using N -bromoamides and visible light
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Transformations that selectively functionalize aliphatic C-H bonds hold significant promise to streamline complex molecule synthesis. Despite the potential for site-selective C-H functionalization, few intermolecular processes of preparative value exist. Herein, we report an approach to unactivated, aliphatic C-H bromination using readily available N-bromoamide reagents and visible light. These halogenations proceed in useful chemical yields, with substrate as the limiting reagent. The site selectivities of these radical-mediated C-H functionalizations are comparable (or superior) to the most selective intermolecular C-H functionalizations known. With the broad utility of alkyl bromides as synthetic intermediates, this convenient approach will find general use in chemical synthesis.
- Schmidt, Valerie A.,Quinn, Ryan K.,Brusoe, Andrew T.,Alexanian, Erik J.
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supporting information
p. 14389 - 14392
(2014/12/10)
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- 5-ALKOXY TRYPTAMINE DERIVATIVES
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Novel 5-alkoxy tryptamine derivatives are provided, corresponding to the general formula: STR1 in which R may be alkaline, X may be amino, and Y is various N-heterocyclic or N-branched chain moieties. The compounds show selective binding to 5-HT 1D receptor subtypes, and have potential pharmaceutical utility in manufacture of migraine-treating drugs.
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- PROCESS FOR PREPARING ALPHA,OMEGA-DIAMINO ACIDS
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An improved process for preparing α,ω-diamino acids, such as D,L-homolysine, 2,8-diaminooctanoic acid, ornithine, lysine, or the like, comprising reaction of phthalic anhydride and an amino alcohol in a hydrocarbon solvent; treatment of the resulting phthalimide--N--(CH. sub.2) n--OH derivative, without isolation thereof, with phosphorus tribromide or phosphorous pentachloride; alkylation of diethyl acetamidomalonate with the phthalimide--N--(CH 2) n--chloride or--bromide of the previous step, in the presence of, particularly, sodium hydride/dimethylformamide; standard acid hydrolysis and decarboxylation; selective protection via copper(II) chelation, N-specific acylation with benzyl chloroformate, and decomposition of the amino acid-copper(II) complex with alkaline thioacetamide; standard t-butoxycarbonyl acylation; and deprotection to obtain the desired α,ω-diamino acids.
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- THE REACTIONS OF LITHIUM ESTER ENOLATES WITH N-(ω-BROMOALKYL)PHTHALIMIDES
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In the title reactions, N-(ω-bromoalkyl)phthalimides were ambident electrophiles.The carbanion of straight chain ester enolates (I, R1=H) attacked the carbonyl carbon atom of phthalimide moiety to give several types of compounds.
- Naruto, Shunsuke,Shimakawa, Keiko,Mizuta, Hiroyuki,Uno, Hitoshi,Nishimura, Haruki
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p. 1089 - 1092
(2007/10/02)
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