functionalized heterohelicenes of high optical purity. Photocyclization of 2-(2-naphtho[2,1-b]thienylvinylene)benzo[1,2-b:4,3-b′]dithiophene-5-carboxamide afforded helicenes as a diastereomeric mixture which was readily separated by column chromatography. Removal of the chiral auxiliary from the diastereomers produced 2-methoxycarbonyl-[7]heterohelicene with [α]D −2770° and its enantiomer with [α]D
发现(1 R,2 S,3 R,4 S)-3-
氨基-2-羟基
冰片烷是合成高光学纯度的官能化杂螺旋体的有效手性助剂。2-(2-
萘[2,1-b]
噻吩亚
乙烯基)苯并[1,2-b:4,3-b']二
噻吩-5-羧酰胺的光环化反应得到非对映异构体混合物的螺旋烯,可通过柱色谱法轻松分离。从非对映异构体上除去手性助剂分别产生具有[α] D -2770°的2-甲氧基羰基-[7]杂庚烯和具有[α] D + 2830°的对映体。