New application of flavinderivatives in visiblelight photocatalysis was found. 1-Butyl-7,8-dimethoxy-3-methyl-alloxazine, when irradiated by visiblelight, was shown to allow an efficient cyclobutane ring formation by an intramolecular [2+2]...
Palladium/benzoic acid-catalyzed hydroalkoxylation of alkynes
作者:Isao Kadota、Leopold Mpaka Lutete、Akinori Shibuya、Yoshinori Yamamoto
DOI:10.1016/s0040-4039(01)01207-2
日期:2001.8
The reaction of the internal alkyne 1 with alcohols 2 in the presence of a catalytic amount of Pd(PPh3)4 and benzoic acid in dioxane at 100°C gave the allylic ethers 3 in good to high yields. The reaction proceeds via the palladium/benzoic acid-catalyzedisomerization of the alkyne 1 to allene 6, followed by the addition of alcohols 2 to the π-allylpalladium intermediate 7 formed by the hydropalladation
Visible Light Photocatalysis of [2+2] Styrene Cycloadditions by Energy Transfer
作者:Zhan Lu、Tehshik P. Yoon
DOI:10.1002/anie.201204835
日期:2012.10.8
Hip to be square: Styrenes participate in [2+2] cycloadditions upon irradiation with visible light in the presence of an iridium(III) polypyridyl complex. In contrast to previous reports of visible light photoredox catalysis, the mechanism of this process involves photosensitization by energy transfer and not electron transfer.
Radical Borylative Cyclization of 1,6-Dienes: Synthesis of Boron-Substituted Six-Membered Heterocycles and Carbocycles
作者:Jing Qi、Feng-Lian Zhang、Yun-Shuai Huang、Ai-Qing Xu、Shi-Chao Ren、Zhen-Yu Yi、Yi-Feng Wang
DOI:10.1021/acs.orglett.8b00694
日期:2018.4.20
A radical borylative cyclization reaction of 1,6-dienes was developed to assemble boron-handled six-membered heterocycles and carbocycles. This reaction was initiated by the chemo- and regio-controlled addition of an N-heterocyclic carbene–boryl radical to one of the alkene tethers, followed by an intramolecular 6-exo cyclization to afford a six-membered ring framework. The utility of this method was
Base catalysed rearrangements involving ylide intermediates. Part 4. [1,3] Sigmatropic rearrangements of 4-dimethylaminobutenes and [3,3] sigmatropic rearrangements of 3-dimethylaminohexa-1,5-dienes
作者:Robert W. Jemison、W. David Ollis、Ian O. Sutherland、James Tannock
DOI:10.1039/p19800001462
日期:——
3] sigmatropic rearrangement (11)→(12) of the 9-dimethylamino-9-(1-phenylallyl)fluorene is a stereoselective process (84 : 16) at 170°. Analogous [1,3] rearrangements (16)→(17) of other fluorene derivatives show that the reaction rate is increased by electron donating 9-substituents in the order O– > NMe2 > OMe. Similar substituent effects are observed for the [3,3] Cope rearrangement (25)→(26) of hexa-1