Photoracemization‐Based Viedma Ripening of a BINOL Derivative

Abstract

Viedma ripening is ad eracemizationp rocess that has been used to deracemize ar ange of chiral molecules. The method hast wo major requirements:t he compound needs to crystallize as ac onglomerate and it needs to be racemizable under the crystallization conditions. Although conglomerate formation can be induced in different ways, the number of racemization methods is still ratherl imited. To extend the scope of Viedma ripening, in the present research we applied UV-light-induced racemization in a Viedmar ipening process, and report the successful deracemizationo faB INOL derivative crystallizing as ac onglomerate. Irradiation by UV light activatest he target compound in combination with an organic base, required to promote the excited-state proton transfer (ESPT), leadingt hereaftert o racemization. This offers an ew tool towards the development of Viedma ripening processes, by using ac heap and "green"c atalytic source like UV light to racemize suitable chiral compounds.

Enantiospecific Solid Solution Formation Triggers the Propagation of Homochirality

“…attrition-induced deracemization)-a powerful method to amplify minute enantioimbalances to virtually absolute enantiomeric purity. [19][20][21][22][23][24][25][26][27] Viedma ripening requires racemizable conglomerates, i.e. compounds that (a) crystallize as racemic conglomerates, and (b) racemize in the liquid phase, i.e.…”

Co-crystals of Praziquantel: Discovery by Network-Based Link Prediction

“…a physical mixture of crystals containing a single enantiomer and the coformer). This opens up a window of possibilities for crystallization-based separation techniques such as preferential crystallization 17 and deracemization methods, [18][19][20][21][22] as was recently demonstrated in two separate case studies for co-crystals of racemic compound forming targets. 23,24 Moreover, introducing a chiral coformer can lead either to the formation of a pair of diastereomeric co-crystals or to the formation of an enantiospecific co-crystal (where only one of the target's enantiomers interacts with the chiral coformer).…”

Optical UV Dosimeters Based on Photoracemization of (R)‐(+)‐1,1′‐Bi(2‐Napthol) (BINOL) within a Chiral Nematic Liquid Crystalline Matrix

“…) and its derivatives are known for their ability to photoracemize due to their photoacidity [26,27] and twisted coplanar transitions. [28] This is an interesting property, as BINOLs are usually stable towards thermal racemization due to steric restrictions, [29] although this can be overcome using an acidic or basic environment.…”