866562-23-4Relevant articles and documents
Synthesis of multi-substituted allenes from organoalane reagents and propargyl esters by using a nickel catalyst
Shao, Xue Bei,Zhang, Zhen,Li, Qing Han,Zhao, Zhi Gang
, p. 4797 - 4806 (2018/07/13)
A highly efficient and simple route for the synthesis of multi-substituted allenes has been developed by a nickel catalyzed SN2′ substitution reaction of propargyl esters with organic aluminium reagents under mild conditions, which gave the corresponding multi-substituted allenes in good to excellent yields (up to 92%) and high selectivities (up to 99%) at 60 °C for 6 h in THF. Aryls bearing electron-donating or electron-withdrawing groups in propargyl esters gave products in good yields. In addition, the multi-substituted allenes bearing a thienyl or a pyridyl group were obtained in 95-97% selectivities with isolated yields of 72-83%. Furthermore, the SN2′ substitution reaction worked efficiently with propargyl carbonate compounds as well. On the basis of the experimental results, a possible catalytic cycle has been proposed.
Synthesis of Multisubstituted Allenes via Palladium-Catalyzed Cross-Coupling Reaction of Propargyl Acetates with an Organoaluminum Reagent
Zhang, Zhen,Mo, Song,Zhang, Gang,Shao, Xuebei,Li, Qinghan,Zhong, Ying
, p. 611 - 614 (2017/03/11)
We describe a convenient method for the synthesis of multisubstituted allenes from cross-coupling of propargyl acetates with -organoaluminum reagent: The reaction of propargyl acetates with 1.2 equivalents of organoaluminum reagent mediated by Pd(PPh3)2Cl2 (1 mol%)/Ph3P (2 mol%) and K2CO3 in THF may produce tri- or tetrasubstituted allenes in good to excellent yields (83-94%) and high regio-selectivities (up to 99%) at 60 °C in 3-4 hours.
Gold-catalyzed regioselective hydration of propargyl acetates assisted by a neighboring carbonyl group: Access to α-acyloxy methyl ketones and synthesis of (±)-actinopolymorphol B
Ghosh, Nayan,Nayak, Sanatan,Sahoo, Akhila K.
supporting information; experimental part, p. 500 - 511 (2011/04/17)
A general atom-economical approach for the synthesis of α-acyloxy methyl ketone is demonstrated through regioselective hydration of a wide range of propargyl acetates. Readily available catalyst comprising of 1% Ph 3PAuCl and 1% AgSbF6 in dioxane-H2O efficiently hydrolyzes the terminal alkynes of the propargyl acetate in the absence of acid promoters at ambient temperature within a short time. Effective regioselective hydration is facilitated by the neighboring carbonyl group as demonstrated through 18O-labeling study. Compatibility of functional moieties and tolerance to various acid-labile protecting groups are observed. The catalytic condition is also suitable to perform hydration of TMS-substituted propargyl acetates, even though it requires prolonged reaction time for completion. Stereointegrity of the propargylic acetate is preserved during the hydration. The robustness of the system is successfully demonstrated through gram scale preparation of the product in nearly quantitative yield. The common α-acyloxy methyl ketone is transformed to 1,2-diol and 1,2-amino alcohol derivatives. Synthesis of actinopolymorphol B is achieved for the first time involving hydration of the propargyl acetate as the key step.
