Chiral Symmetry Breaking of Spiropyrans and Spirooxazines by Dynamic Enantioselective Crystallization

Ishikawa, H.; Uemura, Naohiro; Saito, Rei; Yoshida, Yasushi; Mino, Takashi; Kasashima, Yoshio; Sakamoto, Masami

doi:10.1002/chem.201901889

Cited by 10 publications

(2 citation statements)

References 42 publications

(9 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Most of the reported works are based on α-amino acid derivatives by converting them into imines, which then by tautomerization racemize the H atom bearing a stereogenic center (example of Figure ). However, other racemization procedures, through a redox reaction, thermal sigmatropic rearrangement, atropisomerism, and photoisomerization , are being reported. The efficiency of the deracemization and its compatibility in the Viedma procedure have been used for direct absolute asymmetric synthesis and one-pot procedures. ,, In summary, Viedma deracemization is on the way to become part of retrosynthetic analysis for absolute asymmetric synthesis. , Experimental reports improving the mechanical crystal attrition ,− or using other types of selective energy, for example, temperature gradients and temperature cycles, ,,− ultrasound, and photochemical catalysis .…”

Section: Chiral Polarization Forcesmentioning

confidence: 99%

“…203 Most of the reported works are based on α-amino acid derivatives by converting them into imines, 204 which then by tautomerization racemize the H atom bearing a stereogenic center (example of Figure 9). However, other racemization procedures, through a redox reaction, 205 thermal sigmatropic rearrangement, 206 atropisomerism, 207 and photoisomerization 208,209 are being reported. The efficiency of the deracemization and its compatibility in the Viedma procedure have been used for direct absolute asymmetric synthesis and one-pot procedures.…”

Section: Chiral Recognition and Chemical Enantioselective Transformat...mentioning

confidence: 99%

See 1 more Smart Citation

Spontaneous Deracemizations

et al. 2021

View full text Add to dashboard Cite

Spontaneous deracemizations is a challenging, multidisciplinary subject in current chirality research. In the absence of any chiral inductors, an achiral substance or a racemic composition is driven into an enantioenriched or even homochiral state through a selective energy input, e.g., chemical potential, photoirradiation, mechanical grinding, ultrasound waves, thermal gradients, etc. The most prominent examples of such transformations are the Soai reaction and the Viedma deracemization. In this review, we track the most recent developments in this topic and recall that many other deracemizations have been reported for solutions from mesophases to conglomerate crystallizations. A compiled set of simply available achiral organic, inorganic, organometallic, and MOF compounds, yielding conglomerate crystals, should give the impetus to realize new experiments on spontaneous deracemizations. Taking into account thermodynamic constraints, modeling efforts have shown that structural features alone are not sufficient to describe spontaneous deracemizations. As a guideline of this review, particular attention is paid to the physicochemical origin and symmetry requirements of such processes.

show abstract