Invasive pneumococcal diseases (IPDs) remain the leading cause of vaccine-preventable childhood death, even though highly effective pneumococcal conjugate vaccines (PCVs) are used in national immunization programs in many developing countries. Licensed PCVs currently cover only 13 of the over 90 serotypes of Streptococcus pneumoniae (Sp), so nonvaccine serotypes are a major obstacle to the effective control of IPD. Sp serotype 2 (ST2) is such a nonvaccine serotype that is the main cause of IPD in many countries, including Nepal, Bangladesh, and Guatemala. Glycoconjugate vaccines based on synthetic oligosaccharides instead of isolated polysaccharides offer an attractive alternative to the traditional process for PCV development. To prevent the IPDs caused by ST2, we identified an effective ST2 neoglycoconjugate vaccine candidate that was identified using a medicinal chemistry approach. Glycan microarrays containing a series of synthetic glycans resembling portions of the ST2 capsular polysaccharide (CPS) repeating unit were used to screen human and rabbit sera and identify epitope hits. Synthetic hexasaccharide 2, resembling one repeating unit (RU) of ST2 CPS, emerged as a hit from the glycan array screens. Vaccination with neoglycoconjugates consisting of hexasaccharide 2 coupled to carrier protein CRM197 stimulates a T-cell-dependent B-cell response that induced CPS-specific opsonic antibodies in mice, resulting in killing of encapsulated bacteria by phagocytic activity. Subcutaneous immunization with neoglycoconjugate protected mice from transnasal challenge with the highly virulent ST2 strain NCTC 7466 by reducing the bacterial load in lung tissue and blood.

A direct asymmetric one‐pot synthesis of optically active 2,3‐dihydropyrroles from propargylated malononitrile and N‐Boc‐protected (Boc=tert‐butoxycarbonyl) imines is presented. The approach is based on a bifunctional organocatalytic Mannich‐type reaction and a subsequent gold‐catalyzed alkyne hydroamination and isomerization. The compatibility of both catalytic systems is presented and the overall transformation results in good yields (up to 70 %) with high selectivities (endo/exo>10:1) and enantioselectivities (up to 88 % ee). The absolute configuration of the final products is unambiguously established by X‐ray analysis. To highlight the synthetic potential of the accessed heterocyclic compounds, their transformation into 1‐pyrrolines, which represent direct precursors of pyrrolidines, is presented.

An efficient electromediated aerobic ipso-hydroxylation reaction of aryl and alkyl boronic acids has been developed. Furthermore, mechanistic insight into the role of superoxide anions in this reaction has also been provided based on electrochemical studies and experimental results.

The formal addition of ammonia to nitroalkenes, affording optically active β‐amino nitro compounds in high yields and enantioselectivities, is presented (see scheme). The approach is based on a novel thiourea‐catalyzed aza‐Michael reaction, by which benzophenone imine serves as a masked ammonia equivalent, which is released by hydrolysis.

The first catalytic enantioselective synthesis of oxaziridines is presented. The oxidation of aryl and alkyl aldimines with m-CPBA under organocatalytic conditions using cinchona alkaloid-derived catalysts furnished optically active oxaziridines in good yields and high enantioselectivities (up to 94% ee). Mechanistic investigations indicate a stepwise enantioselective oxidation process.