Achiral inorganic gypsum (CaSO ⋅2 H O) triggers the asymmetric autocatalysis of pyrimidyl alkanol on its two-dimensional enantiotopic faces to give highly enantioenriched alkanol products with absolute configurations corresponding to the respective enantiotopic surfaces. This is the first example of highly enantioselective synthesis on the enantiotopic surface of an achiral mineral.

Asymmetric autocatalysis initiated by chiral crystals containing racemic DL-serine was achieved. P- and M-crystals of DL-serine acted as the source of chirality of asymmetric autocatalysis to afford highly enantioenriched (>99.5% ee) (S)- and (R)-pyrimidylalkanols after the amplification of ee. This is the first example of the usage of the crystal, which contains the same number of D- and L-enantiomers as an origin of chirality in enantioselective synthesis.

Achiral inorganic gypsum (CaSO 4 ·2 H 2 O) triggers the asymmetric autocatalysis of pyrimidyl alkanol on its twodimensional enantiotopic faces to give highly enantioenriched alkanol products with absolute configurations corresponding to the respective enantiotopic surfaces. This is the first example of highly enantioselective synthesis on the enantiotopic surface of an achiral mineral.The origins of the homochirality of biological compounds such as l-amino acids and d-sugars have been the subject of great interest in chemistry, biology, physics, astrobiology, and studies on the origin of life. [1] There have been several theories proposed for the origins of the chirality of organic compounds.Meanwhile, increasing attention has been focused on twodimensional surface chirality. [1n,o, 2] Although chiral inorganic minerals have been considered to be an origin of chirality, achiral natural minerals with an enantiotopic surface have rarely been considered as an origin of chirality. A spectacular example was reported by Hazen et al. [3] They reported the enantiomer-selective adsorption of racemic amino acids on the enantiotopic faces of the achiral mineral calcite (CaCO 3 ) with moderate enantiomeric excess (Scheme 1 a). Certain metal surfaces, such as artificially cut Cu(643), become enantiotopic, and the enantiomer-selective decomposition of chiral compounds have been reported. [4] However, it has not yet been possible to control the enantioselective synthesis induced on the enantiotopic surface of achiral inorganic minerals to generate chiral molecules from achiral molecules.We have been studying asymmetric autocatalysis of pyrimidyl alkanol with amplification of chirality. [5][6][7][8] Various chiral factors, [9] including circularly polarized light, [10] isotope chirality, [11] and chiral inorganic crystals [12] trigger asymmetric autocatalysis. However, to the best of our knowledge, no definitive report has appeared on asymmetric synthesis using achiral inorganic crystals. [13] Gypsum is a common mineral that has been used in a wide range of applications, including materials for sculpture, plasterboard in buildings, and plaster casts for medical use. The crystal structure of gypsum is achiral, but its large grown face and its habit of cleavage make it enantiotopic. Although Cody and Cody have reported asymmetric crystal growth of the enantiotopic surface of gypsum in the presence of a chiral organic compound, [14] and Viedma, Cintas, et. al. have reported oriented aggregation growth of gypsum crystals, [15] no example has been reported of asymmetric synthesis on gypsum enantiotopic surfaces.Herein, we report enantioselective synthesis using the two-dimensional enantiotopic face of an achiral inorganic crystal (Scheme 1 b). The achiral inorganic mineral gypsum (calcium sulfate dihydrate, CaSO 4 ·2 H 2 O) triggers asymmetric autocatalysis on its enantiotopic face, thereby providing highly enantioenriched alkanol product with chirality corresponding to that of the enantiotopic face of the gypsum.Gypsum exhibits a p...

5-Pyrimidyl alkanol with an enantiomeric excess of up to >99.5% was formed using chiral crystals of achiral tris(2-hydroxyethyl) 1,3,5-benzenetricarboxylate as a chiral initiator.In the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, the helicity of the molecular arrangement of achiral tricarboxylate in the crystalline state could be successfully used as a source of chirality to afford enantioenriched alkanol in conjunction with asymmetric autocatalysis with amplification of enantiomeric excess.Spontaneous chiral crystallization of achiral compounds is suspected as a possible origin of biological homochirality such as that found in L-amino acids and D-sugars.1 There are achiral organic compounds that crystallize in chiral space groups to form enantiomorphous crystals.2 Stereospecific reactions have been reported to form enantioenriched organic compounds using enantiomorphous crystals as reactants in the solid state. 2We have been studying asymmetric autocatalysis with amplification of enantiomeric excess (ee), 36 in which a chiral product acts as the chiral catalyst for its own production. Chiral crystals formed from achiral compounds can act as the source of chirality in the addition reaction of dialkylzinc to aldehyde to give a highly enantioenriched product in combination with asymmetric autocatalysis. 7 In this process, the spontaneously generated chiral crystals of the achiral molecules induce enantioselectivity upon the organic compound, and then the asymmetric autocatalysis increases the initial tiny imbalance of chirality to afford a large amount of enantioenriched organic compound. Asymmetric autocatalysis with amplification of ee can correlate the origins of chirality with the homochirality of organic compounds. Azumaya, Yokozawa, and co-workers reported that tris(2-hydroxyethyl) 1,3,5-benzenetricarboxylate (1) formed helically arranged enantiomorphous crystals, which belong to the chiral space group P6 1 or P6 5 (Scheme 1). 9 The planar molecules 1 helically connected with neighboring molecules to generate chirality in the crystalline state by aromaticaromatic interactions and hydrogen bonds. Because the columnar stacks within individual crystals have the same sense of helicity, the crystal shows chirality.Asymmetric synthesis 10 and separation 11 using a chiral substance with helical structure 12 are an intriguing research topic in chiral chemistry. In this paper, we report on the use of chiral crystals of tricarboxylate 1 as a chiral inducer in asymmetric autocatalysis. Therefore, highly enantioenriched organic compounds can be synthesized based on the helicity of 1 in conjunction with asymmetric autocatalytic amplification of ee (Scheme 2).The enantiomorphs of 1 could be obtained by stirred crystallization from methanol solution (Scheme 1). The chirality of the crystal can be discriminated by using the solid-state circular dichroism (CD) spectrum; therefore, right-handed Pcrystals of 1 show a positive Cotton effect at 224 nm with the KBr method ([CD(+)224 KBr ]-1), while...