A general
method for the highly enantioselective desymmetrization
of 2-alkyl-substituted 1,3-diols is presented. A combination of computational
and experimental studies has been utilized to understand the origin
of the stereocontrol of oxidative desymmetrization of 1,3-diol
benzylideneacetals. DFT calculations demonstrate that the acetal
protecting group is highly influential for high enantioselectivity,
and a simple but effective new protecting group has been designed.
The desymmetrization reactions proceed with high enantioselectivity
for a variety of substrates. Moreover, the reaction conditions are
also shown to be effective for desymmetrization of 2,2-dialkyl-substituted
1,3-diols, which provides chiral products bearing acyclic all-carbon
quaternary stereocenters. The method has been applied to the
formal synthesis of indoline alkaloids.
Two pairs of pure E/Z isomers of novel BF2 acylhydrozone dyes have been synthesized, which exhibited AIE, viscosity, crystallization, and acid–base-induced emission.
Molecular refrigerators consisting of unusual fourth‐row metal‐ion–lanthanide complexes with bridging fluoride ions are presented by M. Evangelisti and J. Bendix in their Communication on The combination of lightweight auxiliary ligands and tunable interactions by choice of metal ion makes these systems interesting modules for low‐temperature cooling applications.
DO = 1,4-dioxane) have been obtained from the reaction of H 4 M and TPMA in different solvents by two assemble methods and characterized by elemental analysis, IR, TG, PL, powder and single-crystal X-ray diffraction. Structural analyses indicate that the nature of the solvent molecules can effectively influence the ···(-SO 3 )··· (-15 NH 3 )···(solvent)··· patterns, which then result in diverse packing diagrams. In salts 1 and 3, pairs of HTPMA + cations arrange in tail-to-tail mode to form column motifs which are extended the layers of H 2 M 2dianions into pillared layered network. On the contrary, pairs of HTPMA + cations in salt 2 arrange in head-to-head mode and form layer structures together with pairs of H 2 M 2dianions. The HTPMA + cations and H 2 M 2dianions in salts 4 and 6 are alternately arranged to form column motif, which then 20 pack with each other to form supramolecular network. Pairs of head-to-head HTPMA + cations in salts 7-9 are sandwiched between the -SO 3 groups through hydrogen bonding interactions, generating graphite-like structure. The HTPMA + cations in salts 5 and 10-12 arrange in tail-to-tail mode to form column motifs which are then sandwiched between biphenyl rings instead of the -SO 3 groups. Moreover, different assemble processes are also responsible for diverse structures. Small solvent molecules, such as H 2 O and 25 MeOH, tend to form different structures (1 and 2, 3 and 4), while large molecules usually present the same structures (6-12). It is interesting to note that salt 4 can transform into salt 5 after being exposed to the air for several hours. Luminescent investigation reveals that the emission maximum of salts 1-12 varies from 365 to 371 nm.
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