Branched Hydrosilane Oligomers as Ideal Precursors for Liquid‐Based Silicon‐Film Deposition

Herein a convenient synthetic method to obtain 2,2,3,3‐tetrasilyltetrasilane 3 and 2,2,3,3,4,4‐hexasilylpentasilane 4 on a multigram scale is presented. Proton‐coupled ²⁹Si NMR spectroscopy and single‐crystal X‐ray crystallography enabled unequivocal structural assignment. Owing to their unique properties, which are reflected in their nonpyrophoric character on contact with air and their enhanced light absorption above 250 nm, 3 and 4 are valuable precursors for liquid‐phase deposition (LPD) and the processing of thin silicon films. Amorphous silicon (a‐Si:H) films of excellent quality were deposited starting from 3 and characterized by conductivity measurements, ellipsometry, optical microscopy, and Raman spectroscopy.     

Control of Stereoselectivity in Diverse Hapalindole Metabolites is Mediated by Cofactor-Induced Combinatorial Pairing of Stig Cyclases

Stereospecific polycyclic core formation of hapalindoles and fischerindoles is controlled by Stig cyclases through a three-step cascade involving Cope rearrangement, 6-exo-trig cyclization, and a final electrophilic aromatic substitution. Reported here is a comprehensive study of all currently annotated Stig cyclases, revealing that these proteins can assemble into heteromeric complexes, induced by Ca²⁺, to cooperatively control the stereochemistry of hapalindole natural products.