S-Oxidation products of (+)-thiomicamine-derived oxazolines—promising substrates in the synthesis of alkyl methyl sulfoxides
摘要:
Highly stereoselective oxidation of the 4-methylthio substituent in oxazolines 2-4, derived from (+)-thiomicamine 1, performed using the Kagan procedure and with the vanadium/chiral salen catalytic system, afforded R-s and S-s diastereomeric sulfoxides 5-7, respectively. The reaction of sulfoxide R-s-6 with n-butyl- and tert-butyllithium reagents produced the corresponding butyl methyl sulfoxides in high enantiomeric excess and with an (S) absolute configuration, albeit in moderate yields. (C) 2005 Elsevier Ltd. All rights reserved.
Enantioselective modification of the Pomeranz–Fritsch–Bobbitt synthesis of tetrahydroisoquinoline alkaloids synthesis of (−)-salsolidine and (−)-carnegine