1:1 and 2:1 Inclusion Complexes of (R,R)-(−)-trans-2,3-Bis(hydroxydiphenyl- methyl)-1,4-dioxaspiro[4.4]nonane with N-Allylfuran-2-carboxanilide Which upon Irradiation in the Solid State Give (−)- and (+)-Photocyclization Products, Respectively

Addition of a peptide fragment on an α‐helical depsipeptide induces α/310‐conjugated helix: Synthesis, crystal structure, and CD spectra of Boc–Leu–Leu–Ala–(Leu–Leu–Lac)3–Leu–Leu–OEt

“…Solid‐state CD using microcrystalline and thin‐film samples has been widely used in the field of inorganic complexes and small organic molecules, and peptides 68–76. In particular, the microcrystalline technique is powerful to obtain crystalline‐specific information.…”

“…The incident polarized light can be partially reflected by the suspended peptide crystals, and probably broaden the bandwidth and weaken the band intensity compared with an idealized spectrum. Many good examples are available in the published papers such as by Kuroda et al 73–76. and Bosnich et al 68.…”

Solid-State Photoreactions in Two-Component Crystals

“…[46][47][48] Irradiation of 1:1 solid b-CD (g-CD) complexes of benzoin acetate gave a photocyclization product exclusively enantioselective photoreactions by using their own chiral hosts. These reactions were either electrocyclic cyclization reactions (Schemes 34 [67][68][69] and 35 [70][71][72][73] ) or [2+2] cycloaddition reactions (Schemes 36 66,74 and 37 72,75 ). Their enantiomeric yields are usually very high.…”

“…76 Recently, the chiral arrangements of the guest molecules in chiral inclusion crystals were conveniently demonstrated by measurement of CD spectra in Nujol mulls. 68,69 This method is useful, because many compounds often do not crystallize into single crystals suitable for the X-ray structural study. Another notable finding is that in the first reaction in Scheme 34, the host (R,R)-(-)-20 and the host (R, R)-(-)-21 afforded the products of opposite optical rotation.…”

“…Recently, however, the CD spectra of a few chiral crystals were successfully measured in KBr 144 and also in Nujol mulls. 68,69 Furthermore, optical activity of chiral crystals can be directly measured by the HAUP (high accuracy universal polarimeter) method. 146 From these studies, it has been demonstrated that the signs of optical rotation of the reactant crystal and the product crystal are the same in the case of the symmetry of the mixed crystal.…”