Efficient Asymmetry Generation in the Synthesis of Oxo‐Rhenium(V) Complex cis‐[ReOCl₂{OCMe₂CMe₂OP(OCMe₂CMe₂O)}py]

Vortex‐induced chiral bifurcation in aggregating insulin

“…17 Although the exact mechanism of this phenomenon is still debated (e.g., as to the role of stirring), it appears that secondary nucleation and spreading of mother crystal by hydrodynamic flows play therein an essential part. 1,[18][19][20][21][22] A spontaneous symmetry breaking may also be evoked without stirring by other physicochemical factors dumping competitive de novo formation of chiral seeds, so that the first randomly ''elected'' crystal could spread its chiral phenotype throughout the bulk sample, as is the case of the spontaneous chiral resolution on crystallization of a lariat-type macrocyclic compound.…”

Asymmetric autocatalysis: crystallization-induced highly enantioselective synthesis of a conglomerating oxo-rhenium(V) complex

“…[50][51][52] The cis-with trans-equilibrium reported in those papers is further discussed here in connection with three precursor reactions used to make the desired equilibrating rhenium complex. We focus on the synthesis, illustrated in Scheme 1, of chiral cis-ReOCl 2 (P $ O)py cis-1 as a conglomerate of C-(+) 589 and A-(À) 589 enantiomers, which can be accomplished from optically inactive substrates in several ways.…”

“…However, if the system reacts under strongly disturbed conditions, yet without seeding, it evolves to a bifurcated bimodal one, with a random distribution of the enantiomers. 50 Finally, additional seeding and physical perturbations cause the system to undergo an autocatalytic symmetry breaking process at the same reaction time, yielding a product with one enantiomer in excess, with the same handedness as the seeds. To rationalize this autocatalytic process, one can point to the prerequisite initial aggregation in solution of several homochiral molecules as a transient but crucial step in the homochiral crystal growing process.…”

“…In a chelation reaction (1), achiral trans-ReOCl 2 (OEt)py 2 and the optically inactive spirophosphorane HP $ O yield a racemic mixture of cis-1 with the minor formation of trans-1 owing to cistrans equilibration (3), that is, isomerization reaction. 50,52 Secondly, cis-1 can be obtained as a result of the substitution of pyridine for the monodentate ligand L in ReOX 2 (P $ O)L (L = PPh 3 , OPPh 3 ), (2). à Finally, cis-1 can be attained directly from trans-1 through an intrinsic isomerization reaction (3).…”

Chirality of 20‐membered unclosed cryptand: Macroring distortion via lariat arm modification

“…21 In spite of number of works dealing with supramolecular assemblies, strict control over chirality of objects constructed from achiral components still remained a great challenge. [22][23][24][25][26][27][28][29][30][31][32][33][34] It was, however, identified that achiral molecules, particularly macrocyclic structures, may occur as homochiral species in a crystalline form. 35 In recent [This article is part of the Special Issue: Dedicated to Prof. Jacek Gawronski.…”