• 약학회지
• /
• 제41권6호
• /
• pp.837-839
• /
• 1997

We have synthesized and evaluated (1S, 2R)-1-0-(ethoxycarbonyl)methyl-2,3-0-isopropylidene-1-phenyl-1,2,3-trihydroxypropane(5a) as a novel chiral auxiliary for opt ically active alpha-hydroxyesters.

• Bulletin of the Korean Chemical Society
• /
• 제23권5호
• /
• pp.749-757
• /
• 2002

Chiral oxazolidin-2-one is easily prepared from D-mannitol and demonstrated to undergo highly diastereoselective alkylation reactions via lithium imide Z-enolates of its N-acyl derivatives to afford ${\alpha}-branched$ products. Evans syn and non-Evans sy n aldol products were also selectively obtained using this new auxiliary in high diastereomeric purity by simply changing the stoichiometry of TiCl4 and the nature of the amine base. Also, this new auxiliary is employed in diastereoselective Staudinger-type ${\beta}-lactam$ syntheses. Using 2-chloro-1-methylpyridinium iodide as the dehydrating agent, the reaction of auxiliary tethered acetic acid with trans imines gave the desired ${\beta}-lactams$ with cis-selectivity.

• Bulletin of the Korean Chemical Society
• /
• 제33권11호
• /
• pp.3853-3856
• /
• 2012

• Bulletin of the Korean Chemical Society
• /
• 제20권6호
• /
• pp.744-746
• /
• 1999

• Bulletin of the Korean Chemical Society
• /
• 제32권5호
• /
• pp.1741-1744
• /
• 2011

• Bulletin of the Korean Chemical Society
• /
• 제30권12호
• /
• pp.2935-2937
• /
• 2009

Asymmetric glycolate alkylation reactions in the solid phase were investigated for the first time with good stereoselectivities being obtained by using a Wang resin supported 2-imidazolidinone chiral auxiliary.

• 대한화학회지
• /
• 제51권4호
• /
• pp.392-397
• /
• 2007

• Bulletin of the Korean Chemical Society
• /
• 제33권12호
• /
• pp.4223-4226
• /
• 2012

• Bulletin of the Korean Chemical Society
• /
• 제25권1호
• /
• pp.143-146
• /
• 2004

• Bulletin of the Korean Chemical Society
• /
• 제22권9호
• /
• pp.958-962
• /
• 2001

The chiral amine auxiliary mediated stereoselective alkylation reactions of glycinamides 1-6 and 15-17 using phase transfer catalyst (PTC) for liquid-solid extraction are described. The secondary N-(diphenylmethylene) glycinamides 1, 2 and 3 give better selectivities and yields than tertiary N-(diphenylmethylene) glycinamides 4, 5 and 6. Alkylation of the glycinamide 1 and 2 using 18-Crown-6 as a PTC in toluene at $-40^{\circ}C$ gives best selectivities and yields. Alkylations of N-(4-chlorophenylmethylene)glycinamides 15, 16 and 17 under same PTC conditions give $\alpha$, $\alpha-disubstituted$ amino acid derivatives 18, 19 and 20 with low diastereoselectivities.