Kawase M, Saito S, Kurihara T
Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama, Japan.
Chem Pharm Bull (Tokyo). 2000 Sep;48(9):1338-43. doi: 10.1248/cpb.48.1338.
Alpha-trifluoromethylated acyloins (2 and 6) have been prepared from alpha-hydroxy acids (1), N-acylprolines (5) or N-acyl-N-alkyl alpha-amino acids (8) by novel transformation reactions with trifluoroacetic anhydride (TFAA) in the presence of pyridine. The former reaction of 1 could proceed through mesoionic 1,3-dioxolium-4-olates, whereas the latter two reactions of alpha-amino acids (5 and 8) could involve mesoionic 1,3-oxazolium-5-olates. The reaction of 1 with TFAA shows more potential for practical applications because of the ready availability of the starting materials and ease of manipulation.
α-三氟甲基化偶姻（2和6）是由α-羟基酸（1）、N-酰基脯氨酸（5）或N-酰基-N-烷基α-氨基酸（8）通过在吡啶存在下与三氟乙酸酐（TFAA）进行新型转化反应制备而成。1的前一种反应可能通过中离子型1,3-二氧杂环戊烯-4-醇盐进行，而α-氨基酸（5和8）的后两种反应可能涉及中离子型1,3-恶唑-5-醇盐。1与TFAA的反应由于起始原料易于获得且操作简便，在实际应用中显示出更大的潜力。
