Three-Step Metal-Promoted Allene-Based Preparation of Bis(heterocyclic) Cyclophanes from Carbonyl Compounds Benito Alcaide Pedro Almendros M. Teresa Quirós Carlos Lázaro M. Rosario Torres 10.1021/jo500993x.s001 https://acs.figshare.com/articles/journal_contribution/Three_Step_Metal_Promoted_Allene_Based_Preparation_of_Bis_heterocyclic_Cyclophanes_from_Carbonyl_Compounds/2277520 A straightforward metal-mediated method for the synthesis of bis­(dihydrofuryl) cyclophane scaffolds from carbonyl compounds has been developed. The combination of the dihydrofuran moiety with different heterocycles such as β-lactams and sugars allows high levels of skeletal diversity. The process comprises indium-promoted one-pot carbonyl bis­(allenylation) and gold- or palladium-catalyzed double cyclization in the resulting bis­(allenols), followed by selective ruthenium-catalyzed macrocyclization. In some cases, the method has been successfully applied to the synthesis of the challenging <i>Z</i>-isomers. The <i>E</i>- versus <i>Z</i>-stereochemistry of the metathesis-formed double bonds could not be assigned taking into consideration the usual coupling constants criteria, but a diagnostic based on the chemical shifts of the two olefinic protons located at the macrocyclic double bond was established. 2014-07-03 00:00:00 constants criteria carbonyl compounds bond method olefinic protons bi dihydrofuran moiety chemical shifts Carbonyl CompoundsA synthesis