Chiral bicyclo[3.3.0]octadienes carrying two alkoxy- or alkynyloxy side chains are highly valuable ligands for asymmetric catalysis but have never been explored regarding their liquid crystalline self-assembly. Therefore, a series of bicyclo[3.3.0]octadienes was synthesised and studied by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X-ray diffraction (XRD) to understand the role of the terminal alkyne unit in the side chain. Dienes with hexinyloxy or octinyloxy side chains behaved similar to the diene with hexyloxy chains, showing broad SmA phases and a pronounced tendency for supercooling. In contrast, dienes with mono- or diethylenglycolpropargylic ether chains displayed a decreased phase range and monotropic behaviour in the latter case, while the corresponding diene with propargylether side chains was non-mesomorphic.

The efficacy of heterogeneous catalysis relies heavily on diffusion and distribution of reactants within catalyst supports. However, the presence of confinement, essential for reaction selectivity, drastically slows down molecular transport. Here, macro-mesoporous silica inverse opal (SiO2-IO) films were used as a model system to study the rather unexplored molecular infiltration behavior using a probe molecule resembling a catalyst via confocal laser scanning microscopy (CLSM). CLSM analysis revealed homogeneous tracer distribution in SiO2-IO and attachment to both transport and mesopores. Bulk macro-mesoporous SiO2-IO support was used for the attachment of mono- and bis-functionalized chiral Rh-diene complexes, and the catalytic activity and selectivity with respect to the support was studied. Lower enantioselectivity was observed with the bis-functionalized ligand due to ligand entanglement and reduced accessibility of the active site, while the mono-functionalized ligand gave an excellent enantioselectivity of 94 %ee in the asymmetric 1,2-addition of triphenylboroxine to N-tosylimines and could be recycled up to three times.

Functionalized hydropentalenes (i.e., bicyclo[3.3.0]octanones) constitute important building blocks for natural products and for ligands for asymmetric catalysis. The assembly and tailored functionalization of this convex roof-shaped scaffold is challenging and has motivated a variety of synthetic approaches including our own contributions, which will be presented in this account.1 Introduction2 Biosynthesis of Hydropentalenes3 Hydropentalenes through the Pauson–Khand Reaction4 Hydropentalenes through Transannular Oxidative Cyclization of Cycloocta-1,4-diene5 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Dodecahydrocyclopenta[a]indenes6 Functionalization of Bicyclo[3.3.0]octan-1,4-diones to Crown Ether Hybrids7 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Cylindramide8 Tandem Ring-Opening Metathesis/Ring-Closing Metathesis/Cross-Metathesis of Bicyclo[2.2.1]heptanes9 Functionalization of Bicyclo[3.3.0]octan-1,4-dione to Geodin A10 Hydropentalenes through Enantioselective Desymmetrization of Weiss Diketones11 Functionalization of Weiss Diketones by Carbonyl Ene Reactions12 Functionalization of the Weiss Diketone to Cylindramide and Geodin A Core Units13 Biological Properties of Bicyclo[3.3.0]octanes14 Hydropentalenes through Vinylcyclopropane Cyclopentene Rearrangement15 Functionalization of Bicyclo[3.3.0]octanes toward Chiral Dienes16 Miscellaneous Syntheses of Hydropentalenes17 Conclusion and Outlook

The role of liquid confinement on the asymmetric Rh catalysis was studied using the 1,2-addition of phenylboroxine (2) to N-tosylimine 1 in the presence of [RhCl(C2H4)(2)](2) and chiral diene ligands as benchmark reaction. To get access to Rh complexes of different polarity, enantiomerically pure C-2-symmetric p-substituted 3,6-diphenylbicyclo[3.3.0]octadienes 4 and diastereomerically enriched unsymmetric norbornadienes 5 and 6 carrying either the Evans or the SuperQuat auxiliary were synthesized. A microemulsion containing the equal amounts of H2O/KOH and toluene/reactants was formulated using the hydrophilic sugar surfactant n-octyl beta-d-glucopyranoside (C(8)G(1)) to mediate the miscibility between the nonpolar reactants and KOH, needed to activate the Rh-diene complex. Prominent features of this organized reaction medium are its temperature insensitivity as well as the presence of water and toluene-rich compartments with a domain size of 55 angstrom confirmed by small-angle X-ray scattering (SAXS). Although bicyclooctadiene ligands 4 a,b,e performed equally well under homogeneous and microemulsion conditions, ligands 4 c,d gave a different chemoselectivity. For norbornadienes 5, 6, however, microemulsions markedly improved conversion and enantioselectivity as well as reaction rate, as was confirmed by kinetic studies using ligand 5 b.

Condensation of N,N′‐disubstituted ethylenediamines with BF3·OEt2, in the presence or absence of an auxiliary base, gives mixtures of 2‐fluoro‐1,3,2‐diazaborolidines and ammonium tetrafluoroborates, respectively. Using BF3·NEt3 as the reactant allows the introduction of the boron source and the auxiliary in a single component, but suffers from the inhibition of the cyclisation by an excess of free amine formed as a by‐product. In contrast, rapid and quantitative consumption of the starting materials is observed when the reaction is carried out with a 2:1 mixture of BF3·NEt3 and BF3·OEt2 per mol of ethylenediamine at elevated temperature. Extremely short reaction times are achieved by conducting the reaction in a superheated solution in a microwave reactor. The 2‐fluoro‐1,3,2‐diazaborolidines formed under these conditions are readily isolated in high yields, and their synthetic usability is demonstrated by reactions with lithium phosphanides to give 2‐phosphanyl‐1,3,2‐diazaborolidines. Both the F‐ and R2P‐substituted N‐heterocyclic boranes are fully characterised. In addition, the structural characterisation of an unprecedented BF3 complex of Hünig's base (iPr2EtN) and of a 1,3,2‐diazaborolidine–BF3 complex is reported.