| Title: | "Stereoselective Synthesis and Retentive Trapping of alpha-Chiral Secondary Alkyllithiums Leading to Stereodefined alpha,beta-Dimethyl Carboxylic Esters" |
| Author(s): | Morozova V; Moriya K; Mayer P; Knochel P; |
| Address: | "Department Chemie, Ludwig-Maximilians-Universitat Munchen, Butenandtstrasse 5-13, 81377, Munchen, Germany. Department Chemie, Ludwig-Maximilians-Universitat Munchen, Butenandtstrasse 5-13, 81377, Munchen, Germany. Paul.Knochel@cup.uni-muenchen.de" |
| ISSN/ISBN: | 1521-3765 (Electronic) 0947-6539 (Linking) |
| Abstract: | "The treatment of alpha-chiral secondary alkyl iodides with tBuLi at -100 degrees C leads to the corresponding secondary alkyllithiums with high retention of configuration. Subsequent quenching with various electrophiles such as Bu2 S2 , DMF, MeOB(OR)2 , or Et2 CO provides the desired products with retention of configuration. Furthermore, a transmetalation with CuBr?naP(OEt)3 also allows retentive trapping with acid chlorides and ethylene oxide. The quenching of the resulting alkyllithiums with ClCO2 Et furnishes stereoselectively syn- and anti-ethyl-2,3-dimethyl ester carboxylates (d.r.>94 %). Related esters bearing three adjacent stereo-controlled centers (stereotriads) have also been prepared. This method has been applied to the synthesis of the ant pheromone (+/-)-lasiol in 26 % overall yield (four steps) with d.r.=97:3 starting from commercially available cis-2,3-epoxybutane" |
| Keywords: | carboxylic acids copper lithium pheromone stereotriads; |
| Notes: | "PubMed-not-MEDLINEMorozova, Varvara Moriya, Kohei Mayer, Peter Knochel, Paul eng Germany 2016/05/04 Chemistry. 2016 Jul 11; 22(29):9962-5. doi: 10.1002/chem.201601911. Epub 2016 Jun 8" |
