Graduate School of Biomedical Sciences , Nagasaki University , 1-14 Bukyo-machi , Nagasaki 852-8521 , Japan.
Osaka University of Pharmaceutical Sciences , Osaka 569-1094 , Japan.
Org Lett. 2018 Dec 21;20(24):7830-7834. doi: 10.1021/acs.orglett.8b03331. Epub 2018 Nov 30.
A chiral three-membered ring C-disubstituted α-amino acid ( R, R)-Acc, in which the α-carbon is not a chiral center, but two side chain β-carbons are chiral centers, was synthesized from dimethyl l-(+)-tartrate, and its homopeptides were prepared. X-ray crystallographic analysis of ( R, R)-Acc pentapeptide showed bent left-handed ( M) 3-helical structures with an unusual intramolecular hydrogen bond of the N-H···O (ethereal) type. The left-handedness of the bent helices was exclusively controlled by the side-chain β-carbon chiral centers.
一种手性三元环 C-二取代的α-氨基酸（R,R）-Acc，其中α-碳不是手性中心，而是两个侧链β-碳是手性中心，由二甲基 L-（+）-酒石酸合成，并制备了其同肽。（R,R）-Acc 五肽的 X 射线晶体学分析表明，其具有弯曲的左手（M）3-螺旋结构，具有不寻常的分子内 N-H···O（醚）型氢键。弯曲螺旋的左手性仅由侧链β-碳手性中心控制。
