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[Image: see text] Enantioenriched aldehydes are produced through asymmetric hydroformylation of styrene derivatives using BIBOP type ligands. The featured example is enantioselective synthesis of 4-methyl-3,4-dihydroisocoumarin, which was prepared in a 95.1:4.9 enantiomeric ratio from asymmetric hydroformylation of ethyl 2-vinylbenzoate, then in situ lactonization during reduction process. The conditions are compatible with both electron-rich and electron-poor substituents.

The evolution of a more reactive chiral vanadium catalyst for enantioselective oxidative coupling of phenols is reported, ultimately resulting in a simple monomeric vanadium species combined with a Bronsted or Lewis acid additive. The resultant vanadium complex is found to effect the asymmetric oxidative ortho-ortho coupling of simple phenols and 2-hydroxycarbazoles with good to excellent levels of enantioselectivity. Experimental and quantum mechanical studies of the mechanism indicate that the additives aggregate the vanadium monomers. In addition, a singlet to triplet crossover is implicated prior to carbon-carbon bond formation. The two lowest energy diastereomeric transition states leading to the enantiomeric products differ substantially with the path to the minor enantiomer involving greater torsional strain between the two phenol moieties.

One of the most ubiquitous stabilizing forces in nature is the hydrogen bond, exemplified by the folded secondary, tertiary, and higher-order structure of biomolecules. Despite the fundamental importance of hydrogen bonding, dependence on this stabilizing force places limitations on nature's proteinogenic building blocks. Herein, we demonstrate that replacement of the strictly conserved glycine in collagen with aza-glycine has profound consequences on the stability and self-assembly of collagen peptides by providing an extra hydrogen bond donor. The additional hydrogen bond provided by aza-glycine allows for complete replacement of glycine residues in collagen peptides and truncation to the smallest self-assembling collagen peptide systems observed to date. Our results highlight the vital importance of hydrogen bonding at desolvated interfaces, providing a new strategy for optimization of designed peptide materials and a general solution for stabilizing the collagen triple helix.

Organogenesis and regeneration require coordination of cellular proliferation, regulated in part by secreted growth factors and cognate receptors, with tissue nutrient supply provided by expansion and patterning of blood vessels. Here we reveal unexpected combinatorial integration of a growth factor co-receptor with a heterodimeric partner and ligand known to regulate angiogenesis and vascular patterning. We show that ErbB2, which can mediate epidermal growth factor (EGF) and neuregulin signalling in multiple tissues, is unexpectedly expressed by endothelial cells where it partners with neuropilin 1 (Nrp1) to form a functional receptor for the vascular guidance molecule semaphorin 3d (Sema3d). Loss of Sema3d leads to improper patterning of the coronary veins, a phenotype recapitulated by endothelial loss of ErbB2. These findings have implications for possible cardiovascular side-effects of anti-ErbB2 therapies commonly used for cancer, and provide an example of integration at the molecular level of pathways involved in tissue growth and vascular patterning., Semaphorin ligands and cognate receptors are important in patterning the vasculature. Here, Aghajanian et al. report an unexpected role for ErbB2 in endothelial cells where it partners with Nrp1 to form a novel semaphoring holoreceptor required for embryonic vascular patterning.