A palladium catalyzed efficient synthesis of γ-methylene-α,β-unsaturated γ-lactones via cyclization of 3,4-alkadienoic acids
摘要:
An efficient method was developed for the synthesis of gamma-methylene-alpha, beta-unsaturated gamma-lactones from the Pd-catalyzed cyclization of 3,4-alkadienoic acids. Control experiment shows that the reaction should be carried out under a N-2 atmosphere to ensure the high purity of the products. (c) 2005 Elsevier Ltd. All rights reserved.
A regiodivergent silacarboxylation of allenes under a CO2 atmosphere with PhMe2Si-B(pin) as a silicon source in the presence of a copper catalyst at 70 °C has been developed. The regioselectivity of the reaction is successfully reversed by the proper choice of ligand; carboxylated vinylsilanes are obtained with rac-Me-DuPhos as the ligand, whereas the use of PCy3 affords carboxylated allylsilanes.
在 70 °C 下,在铜催化剂存在下,以 PhMe2Si-B(pin) 作为硅源,在 CO2 气氛下开发了丙二烯的区域发散硅羧化反应。反应的区域选择性通过适当的配体选择成功逆转; 使用 rac-Me-DuPhos 作为配体获得羧化乙烯基硅烷,而使用 PCy3 获得羧化烯丙基硅烷。因此,可以从单个丙二烯底物选择性地和区域发散地合成两种不同的羧化硅烷。