Special delivery! Polyionic complex (PIC) micelles that contain the charge‐conversional moieties citaconic amide or cis‐aconitic amide were developed for cytoplasmic protein delivery. The increase of the charge density on the protein cargo helped the stability of the PIC micelles without cross‐linking, and the charge‐conversion in endosomes induced the dissociation of the PIC micelles to result in efficient endosomal release (see picture).
S ee ing into the future : A range of computational methods have been applied to harmonize predicted ee values with experimental values. Novel ways of combining quantum mechanics and molecular mechanics feature prominently.
Double protection : Efficient Fmoc‐based solid‐phase synthesis (SPPS) of sulfotyrosine (sY) peptides is achieved by incorporating the sY residue(s) as a dichlorovinyl‐protected (DCV) sulfodiester(s) and using 2‐methylpiperidine for Fmoc removal. After removal of the other protecting groups, the DCV group could be cleaved by mild hydrogenolysis giving the sY peptides in good yield.
The Midas touch : The low‐temperature transformation of methanol to methyl formate, formaldehyde, and formic acid is promoted by atomic oxygen adsorbed on metallic gold (see picture). The reactions occur with O‐containing Au nanoparticles formed on Au(111) upon oxidation with ozone at 200 K; the facile esterification to methyl formate occurs well below room temperature.
No hurdle is too high : The regioselectivity and stereoselectivity of the halohydroxylation of non‐activated allenes are controlled by a remote sulfinyl group through anchimeric assistance (see scheme). The resulting halohydrines are excellent chiral targets for the preparation of optically pure propargylic alcohols and Baylis–Hillman‐type products.
One stereocenter makes all the difference : The synthesis and biological evaluation of 17‐epi‐cortistatin A is reported from a common intermediate used to procure natural cortistatin A. The synthesis features a unique stereocontrolled Raney‐Ni reduction process that can be employed to reliably produce both α‐ and β‐configured D‐ring aryl steroids. Biological evaluations of these “cortalogs” are reported for the first time.
Light aqueduct: Periodic mesoporous organosilica exhibits strong light absorption due to densely packed organic chromophores within the pore walls. Light energy absorbed by 125 biphenyl groups in the pore walls is funneled into a single coumarin 1 molecule in the mesochannels with almost 100 % quantum efficiency, and results in significant enhancement of emission from the coumarin 1 dye.
Guest‐love‐ometer : The equilibrium inside–outside atropisomeric ratio of ortho‐substituted phenyl cavitands shows a strong solvent dependence. The competition between the ortho‐substituent and the solvent guest for the bowl cavity leads to a sensitive system for the measurement of relative guest binding affinities.
Well concealed : 1,2‐oxazines such as 1 rearrange under Lewis acidic conditions to bicyclic products of type 2 , which can be incorporated into oligosaccharides as protected amino sugar equivalents. Subsequent reductive steps provide unusual oligosaccharides 3 having C2‐branched 4‐amino sugar units. Most of the reactions proceed with excellent stereocontrol and allow the synthesis of a collection of stereoisomers.
