Regioselective Palladium(II)-Catalyzed Synthesis of Five- or Seven-Membered Ring Lactones and Five-, Six- or Seven-Membered Ring Lactams by Cyclocarbonylation Methodology
作者:Bassam El Ali、Kazumi Okuro、Giuseppe Vasapollo、Howard Alper
DOI:10.1021/ja953403l
日期:1996.1.1
affording five- or seven-memberedring lactones (bicyclic, tricyclic, and pentacyclic) as the principal products, often in excellent yields. Use of 2-aminostyrenes as reactants and catalytic quantities of palladium acetate and tricyclohexylphosphine, affords five-membered ring lactams in high yield and selectivity. Bicyclic and tricyclic heterocycles containing six-membered ring lactams can be synthesized
Copper-catalyzed radical cascade cyclization for the synthesis of phosphorated indolines
作者:Hong-Yu Zhang、Liu-Liang Mao、Bin Yang、Shang-Dong Yang
DOI:10.1039/c4cc10267c
日期:——
A novel and convenient approach to the synthesis of various phosphorated indolinesviaa copper-catalyzed radical cascade cyclization reaction has been developed.
一种新颖且便利的方法已经开发出来,通过铜催化的自由基级联环化反应合成各种磷酸化吲哚。
Catalytic Enantioselective Alkene Aminohalogenation/Cyclization Involving Atom Transfer
作者:Michael T. Bovino、Sherry R. Chemler
DOI:10.1002/anie.201109044
日期:2012.4.16
the synthesis of chiral 2‐bromo, chloro, and iodomethyl indolines and 2‐iodomethyl pyrrolidines (see scheme). Stereocenter formation is believed to occur by enantioselective cis aminocupration and CX bond formation is believed to occur by atom transfer. The ultility of the products as versatile synthetic intermediates was demonstrated, as was a radical cascade cyclization sequence.
已解决的问题:标题反应用于合成手性 2-溴、氯和碘甲基二氢吲哚和 2-碘甲基吡咯烷(参见方案)。立体中心的形成被认为是通过对映选择性顺式 氨基氧化发生的,C X 键的形成被认为是通过原子转移发生的。证明了产品作为多功能合成中间体的实用性,以及自由基级联环化序列。
Efficient Regio- and Stereoselective Formation of Azocan-2-ones via 8-<i>Endo</i> Cyclization of α-Carbamoyl Radicals
作者:Xinqiang Fang、Kun Liu、Chaozhong Li
DOI:10.1021/ja9082649
日期:2010.2.24
The iodine-atom-transfer 8-endo cyclization of alpha-carbamoyl radicals was investigated experimentally and theoretically. With the aid of Mg(ClO4)(2) and a bis(oxazoline) ligand, N-ethoxycarbonyl-substituted N-(pent-4-enyl)-2-iodoalkanamides underwent 8-endo cyclization leading to the formation of only the corresponding 3,5-trans-substituted azocan-2-ones in excellent yields Similarly, the BF3 center dot OEt2/H2O-promoted reactions of N-ethoxycarbonyl-N-(2-allylaryl)-2-iodoalkanamides afforded exclusively the benzazocanone products with a 3,5-cis configuration in high yields The bidentate chelation of substrate radicals not only significantly improved the efficiency of cyclization but also resulted in the change of stereochemistry of azocanone products from 3,8-trans to 3,8-cis Theoretical calculations at the UB3LYP/6-31G* level revealed that the cyclization of N-carbonyl-substituted alpha-carbamoyl radicals occurs via the E-conformational transition states without the presence of a Lewis acid. On the other hand, the cyclization proceeds via the Z-conformational transition states when the substrates form the bidentate chelation with a Lewis acid In both cases, the 8-endocyclization is always fundamentally preferred over the corresponding 7-exo cyclization The complexed radicals having the more rigid conformations also allow the better stereochemical control in the iodine-atom-abstraction step To further understand the reactivity of alpha-carbamoyl radicals, the competition between the 8-endo and 5-exo cyclization was also studied The results demonstrated that the 8-endo cyclization is of comparable rate to the corresponding 5-exo cyclization for alpha-carbamoyl radicals with fixed Z-conformational transition states As a comparison, the 8-endo mode is fundamentally preferred over the 5-exo mode in the cyclization of INIH-amide substrates because the latter requires the Z-conformational transition states, whereas the former proceeds via the more stable E-conformational transition states.
Jain, Seema; Pandey, Neelesh; Kishore, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 2007, vol. 46, # 3, p. 529 - 531