329932-98-1Relevant academic research and scientific papers
Chemoselectivity control: Gold(I)-catalyzed synthesis of 6,7-dihydrobenzofuran-4(5H)-ones and benzofurans from 1-(alkynyl)-7- oxabicyclo[4.1.0]heptan-2-ones
Wang, Tao,Shi, Shuai,Vilhelmsen, Mie Hojer,Zhang, Tuo,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 12512 - 12516 (2013/09/23)
New and chemoselective gold(I)-catalyzed transformations of 1-(arylethynyl)-7-oxabicyclo[4.1.0]- heptan-2-ones were developed. Two completely different products - 6,7-dihydrobenzofuran-4(5H)-ones and benzofurans - could be obtained from the same starting material. The selectivity is determined by the ligand of the gold catalyst: triphenylphosphine delivers 6,7-dihydrobenzofuran-4(5H)-ones, and 1,3-bis(diisopropylphenyl)imidazol-2- ylidene leads to benzofurans. Eleven examples of each case are provided. The mechanistic suggestions for the pathways to both product types are supported by isotope labeling experiments. Complete chemoselectivity control of gold(I)-catalyzed transformations of 1-(arylethynyl)-7-oxabicyclo[4.1.0]heptan- 2-ones, which can be achieved by changing the ligand of the gold catalyst, allows two different products to be obtained from the same starting material, namely, 6,7-dihydrobenzofuran-4(5H)-ones and benzofurans (see scheme), both of which are potent building blocks for synthetic chemistry. IPr: 1,3-bis(diisopropylphenyl)imidazol-2-ylidene. Copyright
Stereospecificity of the Au(I)-catalyzed reaction of 1-alkynyl-bicyclo[4.1. 0]-heptan-2-ones with nucleophiles
Labsch, Stephan,Ye, Shute,Adler, Andreas,Neudoerfl, Joerg-Martin,Schmalz, Hans-Guenther
experimental part, p. 1745 - 1751 (2010/10/03)
The stereospecificity of the Au(I)-catalyzed reaction of 1-alkynyl-bicyclo[4.1.0]-heptan-2-ones with nucleophiles was investigated. The substrates were prepared in non-racemic form (up to 88% ee) through parallel kinetic resolution (CBS reduction) and reo
Strictly regiocontrolled α-monosubstitution of cyclic carbonyl compounds with alkynyl and alkyl groups via Pd-catalyzed coupling of cyclic α-iodoenones with organozincs
Negishi, Ei-Ichi,Tan, Ze,Liou, Show-Yee,Liao, Baiqiao
, p. 10197 - 10207 (2007/10/03)
The conditions for the Pd-catalyzed cross coupling of cyclic α-iodoenones, such as 2-iodo-2-cyclohexenone, with alkynylzincs have been optimized. The use of tris(o-furyl)phosphine (TFP) as a ligand and DMF as a solvent has led to the formation of α-alkynylenones in excellent yields. This optimized procedure has been applied to the synthesis of (±)-harveynone and (±)-tricholomenyn A in high yields. Investigation of related α-alkylation reactions using alkylzincs has revealed the following. Methylzinc and primary alkylzinc derivatives readily undergo Pd-catalyzed cross coupling with α-iodoenones. Although (s-Bu)2Zn also undergoes Pd-catalyzed cross coupling, only the n-Bu-substituted products were obtained, α-Benzylation and α-homobenzylation can proceed satisfactorily, whereas allylzinc and propargylzinc derivatives undergo only addition to the carbonyl group. Although some promising results have been obtained in α-homoallylation and α-homopropargylation, these reactions need to be further improved. (C) 2000 Elsevier Science Ltd.
