Makoto Fukudome

Clockwise–counterclockwise differentiation on the upper rim of a monofunctional γ-cyclodextrin: efficient topological control in the syntheses of capped cyclodextrins

Intramolecular condensation of 6(A)-(N-dansyl-l-cysteine)-gamma-cyclodextrin occurred only at 6(B)-OH of the many OH groups to afford the corresponding lactone with an exo-topology.

The first topologically controlled synthesis of doubly bridged β-cyclodextrin dimers

Reaction 6(A),6(B)-di(O-tosyl)-beta-cyclodextrin with Na(2)S in DMF gave the cis-dimer of beta-cyclodextrin in 21% isolated yield while the trans-dimer was not detected.

Selective sulfonylation of one of the 21 different hydroxyl groups of mono-altro-β-cyclodextrin

Abstract Mono- altro -β-cyclodextrin, which has 21 different hydroxyl groups, has been selectively sulfonylated at the 2-OH of the altrose residue.

Restriction of guest rotation based on the distortion of a cyclodextrin cavity

Significant restriction of the rotation of an intermolecular guest upon binding into a distorted cyclodextrin cavity has been observed for the first time.

Flexible Cyclooligosaccharides: Guest-Binding and Regio-selective Modification

Modified β-cyclodextrin in which one glucopyranose unit is converted into analtropyranose unit showed a guest-induced fit behavior in the inclusion of globular orplanar-shaped guests and brought about, as the result, the regioselective sulfonylationon 2-OH of the altropyranose unit.

Two stereoisomeric 3I, 2II-anhydro-α-cyclodextrins: a molecular dynamics and crystallographic study

Abstract Regioselective epoxide ring opening of 2I,3I-(2IS)-anhydro-α-cyclodextrin (1) through intramolecular attack of hydroxyl groups of neighboring glucose rings occurs in diequatorial fashion to yield 3I,2II-anhydro-α-cyclodextrin (3) with a rigid glucopyranose–dioxane–glucopyranose tricyclic ring system, the usual diaxial opening and the gluco/altro-configurated stereoisomer 2 cannot be detected. Molecular dynamic simulations in water were used to analyze the conformations of 1–3 and the stereochemical implications of this reaction. Due to the contracted 2,3-OH side of the torus, 3 features an inverted conicity compared to the parent α-cyclodextrin. A crystallographic study on the bis-3·3 n-PrOH nonahydrate not only displays little variations between the solid-state and solution geometries of 3, but also provides a molecular picture of a unique inclusion complex in which three n-propanol molecules are distributed in the cavity of a dimeric unit of 3 (monoclinic, space group P21, a=14.257(1), b=22.623(2), c=16.644(1) A, β=104.82(1)°, all 19278 reflections with I>2σ(I) yield R(F)=0.1017).

Cyclodextrin-accelerated cleavage of phenyl esters: is it the 2-hydroxy or the 3-hydroxy that promotes the acyl transfer?

Both 2- and 3-monothiocyclodextrins have been synthesized and used in probing the mechanism of cyclodextrin-mediated cleavage of phenyl esters, showing that the 3-thiols are much more effective than the 2-thiols in promoting the acyl transfer.

The first hetero-bifunctionalization of the secondary face of β-cyclodextrin: selective and efficient conversion of the A-ring of a 2A,2B-disulfonate to 2A,3A-epoxymannoside

The A-ring of 2(A),2(B)-O,O-di(mesitylenesulfonyl)-beta-cyclodextrin was converted to 2(A),3(A)-epoxymannoside without affecting the other sulfonylated residue, which affords the first approach to hetero-bifunctionalization at the secondary hydroxyl side of cyclodextrins.

Selective modification of β-cyclodextrin: an unexpected tandem reaction enables the cross-linking of C2A and C2B via a sulfur atom

2(A),3(A)-Alloepithio-2(B)-sulfonyl-beta-cyclodextrin undergoes a tandem reaction to generate an unprecedented C2(A)-S-C2(B)-bridged glucosyl-3(A),6(A)-anhydroglucoside segment.