Methods are described for the preparation of a range of N,N,N′,N′-tetraalkylformamidinium and N,N-dialkyliminium ions 4–20 as anhydrous salts for use as precursors to diamino- and amino-carbenes. These methods include a novel method involving nucleophilic addition to formamides followed by trapping with electrophiles such as triflic anhydride, various methods of formamide activation, exchange reactions involving orthoesters and the transamination of amidinium salts, and alkylation methods.
本文描述了一系列N,N,N',N'-四烷基甲酰胺鎓和N,N-二烷基
亚胺鎓离子4-20的制备方法,这些无
水盐可用作二
氨基和
氨基碳烯的前体。这些方法包括一种新颖方法,涉及亲核加成到甲酰胺,随后用
三氟甲磺酸酐等亲电试剂捕获,多种甲酰胺活化方法,涉及原酸酯的交换反应以及脒盐的转
氨反应和烷基化方法。