| Title: | "Regio- and Stereoselective Allylic Substitutions of Chiral Secondary Alkylcopper Reagents: Total Synthesis of (+)-Lasiol, (+)-13-Norfaranal, and (+)-Faranal" |
| Author(s): | Skotnitzki J; Spessert L; Knochel P; |
| Address: | "Department Chemie, Ludwig-Maximilians-Universitat Munchen, Butenandtstrasse 5-13, Haus F, 81377, Munchen, Germany" |
| ISSN/ISBN: | 1521-3773 (Electronic) 1433-7851 (Linking) |
| Abstract: | "Chiral secondary alkylcopper reagents were prepared from chiral secondary alkyl iodides by a retentive I/Li exchange followed by a retentive transmetalation with CuBr?naP(OEt)(3) . Switching the solvent to THF significantly increased their configurational stability and made these copper reagents suitable for regioselective allylic substitutions. The optically enriched copper species underwent S(N) 2 substitutions with allylic bromides (up to >99 % S(N) 2 regioselectivity). The addition of ZnCl(2) and the use of chiral allylic phosphates allowed to switch the regioselectivity towards S(N) 2' substitution (up to >99 % S(N) 2' regioselectivity) and to perform highly selective anti-S(N) 2' substitutions with absolute control over two adjacent stereocenters. This method was applied in the total synthesis of the three ant pheromones (+)-lasiol, (+)-13-norfaranal, and (+)-faranal (up to 98:2 dr, 99 % ee)" |
| Keywords: | allylic substitution copper lithium pheromones zinc; |
| Notes: | "PubMed-not-MEDLINESkotnitzki, Juri Spessert, Lukas Knochel, Paul eng Research Support, Non-U.S. Gov't Germany 2018/11/01 Angew Chem Int Ed Engl. 2019 Jan 28; 58(5):1509-1514. doi: 10.1002/anie.201811330. Epub 2018 Dec 28" |
