Dipartimento di Chimica Ugo Schiff, Università degli Studi di Firenze, Via della Lastruccia 13, 50019 Sesto Fiorentino, FI, Italy.
Amino Acids. 2013 Feb;44(2):769-80. doi: 10.1007/s00726-012-1401-0. Epub 2012 Sep 28.
The stereoselective syntheses of 2-cyclopropyl- and (2S)-2-hydroxymethyl-(3R,4S)-4-hydroxy-β(3)-homoproline are described. The reported amino acids were constructed through 1,3-dipolar cycloaddition of strained alkylidenecyclopropanes with enantiopure pyrroline N-oxides derived from malic acid followed by thermal rearrangement of the adducts in the presence of trifluoroacetic acid. The two-step sequence afforded the homoprolines suitably protected to be directly used as building blocks in peptidomimetic synthesis as proved by the synthesis of the two model mixed α/β/α tripeptides Phe-β(3)-HPro-Val.
描述了 2-环丙基-和（2S）-2-羟甲基-（3R，4S）-4-羟基-β（3）-高脯氨酸的立体选择性合成。所报道的氨基酸是通过马来酸衍生的对映纯吡咯啉 N-氧化物与应变的亚烷基环丙烷的 1,3-偶极环加成反应构建的，然后在三氟乙酸存在下对加成物进行热重排。两步序列提供了适当保护的高脯氨酸，可直接用作肽模拟物合成中的构建块，这已通过合成两种模型混合的α/β/α 三肽 Phe-β（3）-HPro-Val 得到证明。
