Forming Stereogenic Centers in Acyclic Systems from Alkynes |
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Authors: | Dr Roxane Vabre M Sc Biana Island B Sc Claudia J Diehl Prof Dr Peter R Schreiner Prof Dr Ilan Marek |
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Institution: | 1. The Mallat Family Laboratory of Organic Chemistry, Schulich Faculty of Chemistry and Lise Meitner‐Minerva Center for Computational Quantum Chemistry, Technion‐Israel Institute of Technology, Technion City, Haifa 32000 (Israel);2. Institute of Organic Chemistry, Justus‐Liebig University, Heinrich‐Buff‐Ring 58, 35392 Giessen (Germany) |
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Abstract: | The combined carbometalation/zinc homologation followed by reactions with α‐heterosubstituted aldehydes and imines proceed through a chair‐like transition structure with the substituent of the incoming aldehyde residue preferentially occupying a pseudo‐axial position to avoid the two gauche interactions. The heteroatom in the axial position produces a chelated intermediate (and not a Cornforth–Evans transition structure for α‐chloro aldehydes and imines) leading to a face differentiation in the allylation reaction. This method provides access to functionalized products in which three new carbon–carbon bonds and two to three stereogenic centers, including a quaternary one, were created in acyclic systems in a single‐pot operation from simple alkynes. |
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Keywords: | acyclic stereoselection allylation chelation quaternary carbon center zinc carbenoids |
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