• Archives of Pharmacal Research
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• v.28 no.2
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• pp.129-141
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• 2005

(-)-Fumagillol (1), a hydrolysis product of fumagillin, has been synthesized by several group from commercially available 1,2:5,6-di-O-isopropylidene-${\alpha}$-D-allofuranose in a highly stereoselective manner. Chiral centers on C5 and C6 came from D-allofuranose and the asymmetric center on C4 was accomplished by 1,3-chirality transfer using the Claisen rearrangement on a chiral allyl alcohol. Chirality, which is necessary on an epoxide consisting of the spiro-ring system, was diastereoselectively constructed by the well-known reaction, intramolecular ester enolate alkylation (IEEA), which showed that this reaction can be applied to the alpha-alkoxy ester system. The epoxide on the side chain was regioselectively introduced by the difference between the number of substituents on the vinyl groups. This accomplishment proved that IEEA can be a useful tool for the synthesis of complex molecules.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1531-1534
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• 2009

(2S,3R)-3-Hydroxy-2-(hydroxymethyl)-3,6-dihydro-2H-pyridine 8, an important precursor for the synthesis of polyhydroxylated piperidine azasugars, has been prepared from L-serine. Highly stereoselective nucleophilic addition to amino aldehyde 5 gave the corresponding allylic alcohol 6 which proceeded to give dihydro-2H-piridine 7a via a Grubbs II catalyzed RCM. Stereoselective H-bond directed epoxidation of allylic alcohol led to the oxiranyl alcohol 9 which was easily converted to L-deoxyaltronojirimycin by regioselective ring opening.

• Bulletin of the Korean Chemical Society
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• v.16 no.1
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• pp.37-42
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• 1995

Reactions of alkenes and alkynes with the recently discovered isopinocampheylhaloborane-methyl sulfide (IpcBHX·SMe2, X=Cl, Br, I) were investigated in detail in order to establish their usefulness as hydroborating agents. The reagents readily hydroborated alkenes at 50 ℃ and alkynes at 25 ℃ with excellent regioselectivity in placing the boron atom exclusively at the less hindered carbon atom. Especially, the selectivity achieved by the iodo derivative reaches essentially 100%. In addition to that, IpcBHX·SMe2 was applied to the reduction of cyclic ketones to examine its stereoselectivity. The halogen substituent in these reagents plays an important role in the stereoselective reduction. The stereoselectivity increased dramatically with increasing steric size of the substituent. Finally, the iodo derivative achieved highly stereoselective reduction, such selectivity being comparable to that previously achieved with trialkylborohydrides.

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.478-483
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• 1994

Reactions of alkenes and alkynes with thexylhaloborane-methyl sulfide (ThxBHX${\cdot}$SMe$_2$, X= Cl, Br, I) were investigated in detail in order to elucidate the effect of halogen substituent in thexylborane and hence establish their usefulness as hydroborating agent. The reagents readily hydroborated alkenes at $50^{circ}C$and alkynes at $25^{circ}C$ in exceptional regioselectivity. Especially, the selectivity achieved by the bromo and iodo derivative reaches essentially 100%. In addition to that, $ThxBHX{\cdot}SMe_2$ was applied to the reduction of cyclic ketones to examine its stereoselectivity. The halogen substituent in thexylborane plays an important role in the stereoselective reduction. The stereoselectivity increased dramatically with increasing steric size of the substituent. Finally, the iodo derivative achieved highly stereoselective reduction, such selectivity being comparable to that previously achieved with trialkylborohydrides.

• YAKHAK HOEJI
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• v.34 no.5
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• pp.287-290
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• 1990

An efficient stereoselective synthetic route to carbocycle is described. 1,1,2-Trisubstituted cyclopentane was synthesized from allylic carbonate by Pd(0) catalyzed cyclization.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.196-196
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• 2001

Stereoselective metabolism and inhibitory potential of lansoprazole enantiomers were evaluated from the incubational studies of human liver microsomes and eDNA-expressed CYP isoforms in vitro. The formation of lansoprazole sulfone from both enantiomers appeared to be catalyzed by single and low affinity enzyme. Lansoprazole 5-hydroxylation, however, appeared to be mediated by two kinetically distinct CYP enzymes.(omitted)

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.695-699
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• 2009

A short and efficient synthesis of (2S,3S)-safingol from commercially available D-ribo-(2S,3S,4R)-phytosphingosine is described. The highlights of the synthesis are a stereoselective one-pot transformation of a diol into an epoxide under phase transfer catalytic conditions and a regioselective epoxide-opening reduction with a hydride reagent.

• YAKHAK HOEJI
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• v.39 no.1
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• pp.41-47
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• 1995

An efficient and stereoselective synthetic route to the trisubstituted hydroxy cyclopentane as an useful synthetic intermediate for carbaprostacyclin is described. Pd(0)-mediated intramolecular alkylation of allylic carbonate has been employed as a key reaction.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.179.2-179.2
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• 2003

We have developed the novel one-pot synthetic method for regioselective and stereoselective N-protected amines through the reaction of various ethers with chlorosulfonyl isocyanate (CSI). Also, we found a novel technique to compare directly the stability of carbocations in the solution phase and established the stability order of the various carbocations. And we reported the cleavage of benzyl and p-methoxybenzyl protecting groups of alcohols and phenols in the presence of other functional groups using CSI. (omitted)

• Bulletin of the Korean Chemical Society
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• v.17 no.12
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• pp.1106-1106
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• 1996