ChemInform Abstract: Functionalized Triarylcarbenium Ions as Catalysts in Mukaiyama Aldol Addition: Effects of Counter Ions and Silyl Groups on the Intervention of Silyl Catalysis.

ChemInform ◽  
2010 ◽  
Vol 29 (47) ◽  
pp. no-no
Author(s):  
C.-T. CHEN ◽  
S.-D. CHAO ◽  
K.-C. YEN
Keyword(s):  
Counter Ions ◽  
Mukaiyama Aldol ◽  
Silyl Groups ◽  
Aldol Addition

Aromatic aldehyde-selective aldol addition with aldehyde-derived silyl enol ethers

2018 ◽  
Vol 54 (4) ◽  
pp. 374-377 ◽  
Author(s):  
Takahiro Kawajiri ◽  
Reiya Ohta ◽  
Hiromichi Fujioka ◽  
Hironao Sajiki ◽  
Yoshinari Sawama
Keyword(s):  
Aromatic Aldehyde ◽  
Aldol Reaction ◽  
Aliphatic Aldehydes ◽  
Enol Ethers ◽  
Silyl Enol Ethers ◽  
Mukaiyama Aldol Reaction ◽  
Mukaiyama Aldol ◽  
Aldol Addition

Unprecedented chemoselectivity between aromatic and aliphatic aldehydes has been achieved in the Mukaiyama aldol reaction using aldehyde-derived silyl enol ethers.

ChemInform Abstract: A Rapid Injection NMR Study of the Chelation Controlled Mukaiyama Aldol Addition: TiCl4 versus LiClO4 as the Lewis Acid.

ChemInform ◽  
2010 ◽  
Vol 23 (43) ◽  
pp. no-no
Author(s):  
M. T. REETZ ◽  
B. RAGUSE ◽  
C. F. MARTH ◽  
H. M. HUEGEL ◽  
T. BACH ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Nmr Study ◽  
Rapid Injection ◽  
Mukaiyama Aldol ◽  
Aldol Addition

scholarly journals Asymmetric Total Syntheses of Both Enantiomers of Plymuthipyranone B and Its Unnatural Analogues: Evaluation of anti-MRSA Activity and Its Chiral Discrimination

2021 ◽  
Vol 14 (9) ◽  
pp. 938
Author(s):  
Mizuki Moriyama ◽  
Xiaoxi Liu ◽  
Yuki Enoki ◽  
Kazuaki Matsumoto ◽  
Yoo Tanabe
Keyword(s):  
Enantiomeric Excess ◽  
Chiral Discrimination ◽  
Synthetic Analogue ◽  
Synthetic Analogues ◽  
Total Syntheses ◽  
Chiral Compounds ◽  
Mukaiyama Aldol ◽  
Aldol Addition ◽  
Chemical Class

Chiral total syntheses of both enantiomers of the anti-MRSA active plymuthipyranone B and all of the both enantiomers of three unnatural and synthetic analogues were performed. These two pairs of four chiral compounds are composed of the same 3-acyl-5,6-dihydro-2H-pyran-2-one structure. The starting synthetic step utilized a privileged asymmetric Mukaiyama aldol addition using Ti(OiPr)4/(S)-BINOL or Ti(OiPr)4/(R)-BINOL catalysis to afford the corresponding (R)- and (S)-δ-hydroxy-β-ketoesters, respectively, with highly enantiomeric excess (>98%). Conventional lactone formation and successive EDCI-mediated C-acylation produced the desired products, (R)- and (S)-plymuthipyranones B and three (R)- and (S)- synthetic analogues, with an overall yield of 42–56% with a highly enantiomeric excess (95–99%). A bioassay of the anti-MRSA activity against ATCC 43300 and 33591 revealed that (i) the MICs of the synthetic analogues against ATCC 43300 and ATCC 33591 were between 2 and 16 and 4 and 16 μg/mL, respectively, and those of vancomycin (reference) were 1 μg/mL. (ii) The natural (S)-plymuthipyranone B exhibited significantly higher activity than the unnatural (R)-antipode against both AACCs. (iii) The natural (R)-plymuthipyranone B and (R)-undecyl synthetic analogue at the C6 position exhibited the highest activity. The present work is the first investigation of the SAR between chiral R and S forms of this chemical class.

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