Preparation of enantiopure sultams by intramolecular Diels–Alder reaction of furan-containing vinylsulfonamides
摘要:
Enantiomerically pure delta- and gamma-sultams have been prepared by intramolecular [4+2] cycloaddition of N-1-phenylethyl substituted vinylsulforiamides with purely thermal activation and under high pressure, An optimized procedure for reductive debenzylation of the resultant delta-sultams is also reported. (C) 2002 Elsevier Science Ltd. All rights reserved.
New Potentially Chelating Chiral Magnesium Amide Bases for Use in Enantioselective Deprotonation Reactions
作者:William Kerr、Michael Middleditch、Allan Watson
DOI:10.1055/s-0030-1259282
日期:2011.1
to prepare novel chiral magnesium bisamide reagents. These amide bases were subsequently applied within asymmetric deprotonation reactions to probe the potential for chelation-assisted selectivity enhancement. Good levels of selectivity could be achieved (up to 87:13 e.r. (R:S)) across a range of prochiral cyclohexanone substrates when employing a thiophene-derived magnesium bisamide complex.
合成了一系列手性仲胺,结合了 5 或 6 元杂环,并用于制备新型手性镁双酰胺试剂。随后将这些酰胺碱应用于不对称去质子化反应中,以探索螯合辅助选择性增强的潜力。当使用噻吩衍生的镁双酰胺复合物时,可以在一系列前手性环己酮底物上实现良好的选择性(高达 87:13 er (R:S))。
Diastereoselective addition of methyllithium and dimethylcuprate-boron trifluoride to imines derived from (S)-1-phenylethylamine
作者:Giuseppe Alvaro、Diego Savoia、Maria R. Valentinetti
DOI:10.1016/0040-4020(96)00746-6
日期:1996.9
trifluoride reagents with the iminesderivedfrom (S)-1-phenylethylamine afforded the secondary amines by addition to the Si face of the imines. (S,S)-bis(1-phenylethyl)amine and (S)-1-cyclohexylethanamine were prepared with high stereoselectivity, in the latter case by a two step sequence involving the final cleavage of the auxiliary. Methyllithium attacked mainly the Si face of the iminesderivedfrom 4-pyridine