Preparation of enantiopure chiral amino-[D1]methyllithium compounds and determination of their micro- and macroscopic configurational stabilities.
Chiral amino-[D(1)]methyllithiums have been tested with regard to their microscopic and macroscopic configurational stabilities. The N-Boc-N-diethoxyphosphinyl-substituted analogue immediately rearranged, showing complete retention of configuration at up to 0 degrees C. The N-Boc-N-PMB-protected analogue enantiomerized at -78 degrees C, but displayed an ee value of 65% at -95 degrees C under macroscopic conditions when quenched with benzaldehyde seconds after its generation. Isocyanomethyllithium proved to be configurationally labile at this temperature and racemized completely, even on the microscopic timescale. Only the non-stabilized N,N-dibenzylaminomethyllithium was found to be virtually macroscopically configurationally stable below -95 degrees C.
Kapeller
Dagmar C
DC
Department of Organic Chemistry, University of Vienna, Währingerstrasse 38, 1090 Vienna, Austria.
Hammerschmidt
Friedrich
F
D002384:Catalysis; D008094:Lithium / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013696:Temperature
D009942:Organometallic Compounds; C520093:methyllithium; D008094:Lithium