Synthesis of a chiral di(hydroxyalkyl) substituted bicyclic guanidine

Artificial Organic Host Molecules for Anions

“…255 The X-ray structure of 65 revealed formation of the expected host-guest geometry embedded in a larger array of hydrogen bonds. 255 When the first chiral analogues became available 277,278 and the synthesis was improved to give a more reliable and efficient procedure [279][280][281][282][283][284] (Figure 7), extensive use of these anchor groups could be made for enantioselective recognition, catalysis, and specific transport of substrates across membranes. Recently, further progress was made in the derivatization of the parent bicyclic guanidines (cf.…”

Acid-Mediated C–N Bond Cleavage in 1-Sulfonylpyrrolidines: An Efficient Route towards Dibenzoxanthenes, Diarylmethanes, and Resorcinarenes

“…However, it is undoubtedly of interest since it allows the synthesis of bifunctional sulfamide derivatives in a one-step and one-pot manner with good to high yields. [7][8][9][10][11][12][13][14][15] Moreover, most of these reactions are stereoselective, which makes them important for the asymmetric synthesis. 8,9,[16][17][18] Reagents and approaches used for the C-N bond cleavage in N-sulfonylpyrrolidines vary widely.…”

“…[7][8][9][10][11][12][13][14][15] Moreover, most of these reactions are stereoselective, which makes them important for the asymmetric synthesis. 8,9,[16][17][18] Reagents and approaches used for the C-N bond cleavage in N-sulfonylpyrrolidines vary widely. For example, sodium in naphthalene, 19 sodium borohydride, 11 lithium alu-minohydride, 9 and hydrogen with a palladium catalyst 14 were used for the reductive N-sulfonylpyrrolidine ring opening.…”

“…8,9,[16][17][18] Reagents and approaches used for the C-N bond cleavage in N-sulfonylpyrrolidines vary widely. For example, sodium in naphthalene, 19 sodium borohydride, 11 lithium alu-minohydride, 9 and hydrogen with a palladium catalyst 14 were used for the reductive N-sulfonylpyrrolidine ring opening. Usage of Grignard reagents 20,21 and Lewis acids 12,13 are also described.…”

Surprises in the Design of Anion Receptors: Calorimetry Prevents False Reasoning

“…The guanidinium group has a rich history both in biological and artificial receptors . Especially successful examples of the latter class employed the bicyclic version (Figure ), which limits the variety of low-energy guest-binding modes and may additionally be readily incorporated into polytopic hosts following peripheral substitution. − The tetracarboxamide 1 was selected as the primary target because it combines a high density of hydrogen donor functions suitable for anion binding with straightforward options for modification and incorporation into polymodular hosts. Ideally, all hydrogen bond donors should converge with their sticky sides onto the bound guest anion, which as a result would be held in a unique position by strong attractive forces.…”