• Bulletin of the Korean Chemical Society
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• v.17 no.10
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• pp.879-881
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• 1996

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1381-1383
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• 1999

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.99-103
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• 2000

Acid and base catalyzed intramolecular cyclizations of N-benzoylthioureidoacetal, contain-ing four functional groups adjacent to thiourea such as benzocarbamoyl, acetal, thioure and amide, were investigated. The condensation reaction of N-benzoyl thiocarbamoylgly-cine amide in the presence of 10% aqueous NaOH provided 1-(2,2-dimethoxy)ethyl-imi- dazolidine-2-thione exclusively. In the presence of pyridine, it was transformed to 2- thiohydantoin. N-Benzoyl thiocarbamoyl glycine amide was completely transformed to an iminothiazolidine exclusively in the presence of Lewis acid such as borontrifluoride ether-ate or trimethylsilyl iodide. 1-(2,2-Dimethoxy)ethyl-imidazolidine-2-thione was transformed to imidazole[2,1-b]thiazole and pyrazino[5,1-a]imidazole in the presence of $BF_3$.$ET_2$O and formic acid, respectively.

• Bulletin of the Korean Chemical Society
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• v.20 no.6
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• pp.643-647
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• 1999

Hydropalladium carboxylates, formed from π-allylpalladium chloride dimer plus carboxylic acids, have been shown to catalyze cyclization of structurally diverse enediynes to form the corresponding six- or five-membered rings depending upon the reaction conditions. Some enediynes having an Oxygen linker in an appropriate position under the similar condition yielded the corresponding cyclopropanation products in highly stereoselective manner. A study using deuterated formic acid has proven that the alkylpalladium intermediates formed in our conditions were reduced by the pendant formate ligand. The dienediyne 10 yielded only the tricyclic product 12 in 67% yield, although it was expected to frrm the cyclic product 11. All these cyclizations seemed to occur via the corresponding alkylpalladium intermediates I. which could proceed to the corresponding cyclic products depending on the reaction conditions and the substrates. The study using ceuterated formic acid could provide an important information to understand the present cyclization mechanism. Overall the present study could play an important role in developing new synthetic methodologies for constructing complex polycyclic compounds.

• Bulletin of the Korean Chemical Society
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• v.15 no.9
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• pp.701-702
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• 1994

• Bulletin of the Korean Chemical Society
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• v.22 no.11
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• pp.1267-1269
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• 2001

• Journal of the Korean Chemical Society
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• v.49 no.1
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• pp.63-71
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• 2005

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3477-3480
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• 2012

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1627-1628
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• 2004

• Bulletin of the Korean Chemical Society
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• v.19 no.8
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• pp.862-868
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• 1998

The Lewis acid mediated intramolecular additions of allylsilanes to acetal substrates are described. Excellent regio- and diastereoselectivity are achieved by boron trifluoride promoted cyclization of allysilane-acetals 5 and 8 derived from hydroxy allysilances 3. Cyclizations occur in moderate to high yields, providing directr routes to cis-2, 6-disubstituted 4-methylenetetrahydropyrans 6 and 9.