A convenient and efficient visible-light-induced tandem acylation/cyclization of N-propargylindoles with aryl- or alkyl-substituted acyl oxime esters for the synthesis of 2-acyl-substituted 9H-pyrrolo[1,2-a]indoles under transition-metal-free conditions, which proceeds via nitrogen-centered radical-mediated cleavage of the C–C σ-bond in acyl oxime esters, is established. The aryl or alkylacyl radicals
N-炔丙基吲哚与芳基-或烷基-取代的酰基肟酯的方便有效的可见光诱导串联酰化/环化,用于合成2-酰基-取代的9 H-吡咯并[1,2- a ]吲哚过渡建立了无金属条件,该条件通过氮中心自由基介导的酰基肟酯中 C-C σ 键的裂解进行。来自酰基肟酯的芳基或烷基酰基自由基攻击N-炔丙基吲哚中的 C-C 三键,然后进行分子内环化/异构化。
Visible-Light-Induced Dual Acylation of Alkenes for the Construction of 3-Substituted Chroman-4-ones
structural skeletons. Herein, we report a visible-light-induced dual acylation of alkenes for constructing 3-substituted chroman-4-ones, which undergoes a radical tandem cyclization reaction through carbon–carbon bond cleavage of oxime esters by a nitrogen-centered radical strategy. A series of 3-substituted chroman-4-ones were prepared with up to 86% yield.
A nitrogen-centered radical strategy for the preparation of 3-acylated spiro[4,5]trienones via visible-light-mediated acylation/ipso-cyclization of alkynes with acyl oxime esters is reported. The alkyl- and aryl-substituted acylradicals, which generate from the cleavage of carbon-carbon σ-bonds in acyl oxime esters via nitrogen-centered radical pathway, attack the carbon-carbon triple bonds in propiolamides
The effect of acyl substituents on the α-effect: contrasting α-effect profiles for reactions of 4-nitrophenyl substituted benzoates with neutral and anionic nucleophiles
作者:Ik-Hwan Um、Hyun-Joo Han、Eun-Kyung Chung
DOI:10.1016/s0040-4039(01)01719-1
日期:2001.11
The magnitude of the α-effect for reactions of 4-nitrophenyl substituted benzoates with a pair of anionicnucleophiles is independent of the electronic nature of the acyl substituent, while the one for the corresponding reactions with a pair of neutral nucleophiles increases as the acyl substituent changes from a strong electron withdrawing substituent to electron donating ones.
A new photoinduced acylation/arylation of N-(arylsulfonyl)acrylamide with acyl oxime esters through a nitrogen-centered radical protocol has been disclosed for efficient preparation of functionalized indolin-2-ones, which proceeds through a cascade acylradical addition of carbon-carbon double bond, aryl migration, desulfonylation, and intramolecular cyclization sequence. This redox-neutral strategy