Racemic [5]helquat as a triflate salt has been synthesized using a robust, three-step procedure. Subsequent exchange of triflate anions for inexpensive (R,R)-dibenzoyltartrate anions via an ion exchange resin afforded two diastereoisomeric salts. Crystallization led to the resolution of the helquat (ee > 98%). This is the first time that a non-racemic helquat has been obtained; its helicity having been assigned and its racemization barrier determined. Capillary electrophoresis with a sulfated β-cyclodextrin chiral selector is introduced for the first time as a straightforward method to analyze the enantiocomposition of charged, helicene-like species.
                                    合成了外消旋[5]螺烷
三氟甲磺酸盐,采用了一种稳健的三步法。随后,通过离子交换
树脂将
三氟甲磺酸阴离子交换为廉价的(R,R)-
二苯甲酰酒石酸阴离子,得到两种二对映异构盐。结晶导致螺烷的分离(ee > 98%)。这是首次获得非外消旋螺烷;它的螺旋性被确认,且其外消旋障碍被测定。首次引入带有
硫酸化β-
环糊精手性选择剂的毛细管电泳,作为分析带电螺旋烯类物质的对映体组成的简单方法。