Fast Tin-Free Hydrodehalogenation and Reductive Radical Cyclization Reactions: A New Reduction Process
作者:Santiago E. Vaillard、Al Postigo、Roberto A. Rossi
DOI:10.1021/jo035477i
日期:2004.3.1
The photostimulated reactions of several aryl and alkyl chlorides and bromides with the monoanion of reduced ethyl benzoate 5H furnish the reduced products in high yields. If the aryl moieties have suitable double bonds, the cyclized reduced products are obtained in high yields. The photostimulated reaction of 1-allyloxy-2-bromobenzene (1a) with 5H affords 3-methyl-2,3-dihydro-benzofuran (2a) in 97%
Syntheses of 3-Substituted 2,3-Dihydrobenzofuranes, 1,2-Dihydronaphtho(2,1-<i>b</i>)furanes, and 2,3-Dihydro-1<i>H</i>-indoles by Tandem Ring Closure−S<sub>RN</sub>1 Reactions
作者:Santiago E. Vaillard、Al Postigo、Roberto A. Rossi
DOI:10.1021/jo026404m
日期:2002.11.1
3-Substituted 2,3-dihydrobenzofuranes (7a-c), 1,2-dihydronaphtho(2,1-b)furanes (10a-c), and N-substituted 2,3-dihydro-1H-indoles (8a-c, 9a,b) are obtained in very good yields by S(RN)1 photostimulated reactions in liquid ammonia from adequate haloaromatic compounds ortho-substituted with a suitable double bond (3a,b; 4a,b; 5a; 6a,b) and Me3Sn-, Ph2P-, and -CH2NO2 anions. The novelty of the work involves the versatile application of a 5-exo ring closure process during the propagation cycle of the SRN1 reaction; the alkyl radical intermediates formed react with the nucleophiles to afford the ring closure-substituted heterocycles. The factors governing the observed product distribution are discussed.
An approach to the synthesis of naphtho[b]furans from allyl bromonaphthyl ethers employing sequential photoinduced radical cyclization and dehydrohalogenation reactions
A simple method has been developed for the efficient synthesis of naphtho[b]furans from allyl bromonaphthyl ethers. The approach utilizes a novel photochemical process involving sequential radicalcyclization and dehydrohalogenation. Because light is a readily available, environmentally friendly reagent that produces no by-products, the new process serves as a green synthetic method.
已经开发了一种从烯丙基溴萘基醚有效合成萘并[ b ]呋喃的简单方法。该方法利用了涉及顺序自由基环化和脱卤化氢的新型光化学过程。由于光是一种容易获得的,不产生副产物的环保试剂,因此新工艺可作为绿色合成方法。
Dipyrrolidinomethylaminophosphoric acid triamide (DPMPA) as an activator for the samarium diiodide-mediated reduction of alkyl and aryl halides
作者:Chriss E. McDonald、Jeremy R. Ramsey、David G. Sampsell、Laura A. Anderson、Jordan E. Krebs、Samantha N. Smith
DOI:10.1016/j.tet.2013.02.025
日期:2013.4
The use of the conjugate base of dipyrrolidinomethylaminophosphoric triamide (DPMPA−) as an activator of samariumdiiodide is reported. This phosphoramidate has been shown to be a very potent ligand, allowing for the efficient, low-temperature reduction of alkyl and aryl chlorides. Reductive cyclizations of haloalkenylnaphthalenes are also reported.