A [(sec-allyloxy)dimesitylsilyl]stannane bearing a phenyl group on the olefin part reacts with n-BuLi in THF to give a cyclopropylsilane as a single diastereomer, in contrast to the [2,3]-sila-Wittig rearrangement affording an allylsilane, previously observed for a substrate bearing an alkyl group on the olefin part. The striking substituent effect is revealed by ab initio calculations in terms of the regioselectivity in the reaction of silyllithiums with an olefin.
{"title":"Stereoselective Formation of Cyclopropylsilane through Intramolecular Rearrangement of [(Allyloxy)dimesitylsilyl]lithiums (SYNTHETIC ORGANIC CHEMISTRY-Synthetic Design)","authors":"A. Kawachi, Hirofumi Maeda, K. Tamao","doi":"10.1246/CL.2000.1216","DOIUrl":"https://doi.org/10.1246/CL.2000.1216","url":null,"abstract":"A [(sec-allyloxy)dimesitylsilyl]stannane bearing a phenyl group on the olefin part reacts with n-BuLi in THF to give a cyclopropylsilane as a single diastereomer, in contrast to the [2,3]-sila-Wittig rearrangement affording an allylsilane, previously observed for a substrate bearing an alkyl group on the olefin part. The striking substituent effect is revealed by ab initio calculations in terms of the regioselectivity in the reaction of silyllithiums with an olefin.","PeriodicalId":13086,"journal":{"name":"ICR annual report","volume":"32 1","pages":"34-35"},"PeriodicalIF":0.0,"publicationDate":"2000-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84589610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-08-01DOI: 10.1080/10587259908026008
N. Sato, I. Kawamoto, T. Sakuma, H. Yoshida
Abstract To approach a novel molecular assembly with notable electronic properties, a molecular design towards highly amphoteric and polar molecules (HAPMs) as its building blocks is proposed. This design stresses the combination of two different π-molecular segments, electron-donating and accepting ones, particularly with a pseudo-delocalized π-election system. To examine the suggested contrivance, 2-(4-dicyanomethylenecyclohexa-2,5-dienylidene)-4,5-ethylenedithio-1,3-dithiole 1 was designed and synthesized as a test molecule. Semiempirical MO calculations of 1 and its extended quinonoid analogues indicate a moderately strong intramolecular charge-transfer working in the molecules in the ground state. Moreover, several experimental results of 1, e.g., its absorption spectra and cyclic voltammograms, imply that most characteristics expected for HAPM are in principle recognized in 1, though further improvements needed to clear the whole requirements for it.
{"title":"A Molecular Design towards a Highly Amphoteric and Polar Molecule (HAPM) to Assemble Novel Organic Solid-State Structures (INTERFACE SCIENCE-Molecular Aggregates)","authors":"N. Sato, I. Kawamoto, T. Sakuma, H. Yoshida","doi":"10.1080/10587259908026008","DOIUrl":"https://doi.org/10.1080/10587259908026008","url":null,"abstract":"Abstract To approach a novel molecular assembly with notable electronic properties, a molecular design towards highly amphoteric and polar molecules (HAPMs) as its building blocks is proposed. This design stresses the combination of two different π-molecular segments, electron-donating and accepting ones, particularly with a pseudo-delocalized π-election system. To examine the suggested contrivance, 2-(4-dicyanomethylenecyclohexa-2,5-dienylidene)-4,5-ethylenedithio-1,3-dithiole 1 was designed and synthesized as a test molecule. Semiempirical MO calculations of 1 and its extended quinonoid analogues indicate a moderately strong intramolecular charge-transfer working in the molecules in the ground state. Moreover, several experimental results of 1, e.g., its absorption spectra and cyclic voltammograms, imply that most characteristics expected for HAPM are in principle recognized in 1, though further improvements needed to clear the whole requirements for it.","PeriodicalId":13086,"journal":{"name":"ICR annual report","volume":"23 1","pages":"12-13"},"PeriodicalIF":0.0,"publicationDate":"1999-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88727278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In hot water heated up to 250 °C and 4 MPa, methanol and formic acid are produced from the Cannizzaro-type reaction of formaldehyde without a catalyst, although this disproportionation reaction is well-known to occur in the presence of a large amount of base catalysts in ambient conditions. Formic acid further undergoes the hydride transfer reaction with formaldehyde, and the final yield of methanol exceeds 50%.
{"title":"Noncatalytic Cannizzaro-type Reaction of Formaldehyde in Hot Water (INTERFACE SCIENCE-Solutions and Interfaces)","authors":"Y. Tsujino, C. Wakai, N. Matubayasi, M. Nakahara","doi":"10.1246/CL.1999.287","DOIUrl":"https://doi.org/10.1246/CL.1999.287","url":null,"abstract":"In hot water heated up to 250 °C and 4 MPa, methanol and formic acid are produced from the Cannizzaro-type reaction of formaldehyde without a catalyst, although this disproportionation reaction is well-known to occur in the presence of a large amount of base catalysts in ambient conditions. Formic acid further undergoes the hydride transfer reaction with formaldehyde, and the final yield of methanol exceeds 50%.","PeriodicalId":13086,"journal":{"name":"ICR annual report","volume":"25 1","pages":"10-11"},"PeriodicalIF":0.0,"publicationDate":"1999-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87334687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1999-03-01DOI: 10.1678/RHEOLOGY1973.25.4_193
Syozo Murakami, K. Urayama, S. Kohjiya
{"title":"Deformation Behavior of Extruded Blown Film of High Density Polyethylene (STATES AND STRUCTURES- Polymer Condensed States)","authors":"Syozo Murakami, K. Urayama, S. Kohjiya","doi":"10.1678/RHEOLOGY1973.25.4_193","DOIUrl":"https://doi.org/10.1678/RHEOLOGY1973.25.4_193","url":null,"abstract":"","PeriodicalId":13086,"journal":{"name":"ICR annual report","volume":"34 1","pages":"8-9"},"PeriodicalIF":0.0,"publicationDate":"1999-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91447204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-03-12DOI: 10.1016/S0040-4039(97)10848-6
K. Fuji*, T. Kawabata, Takahiro Oka
{"title":"The First Synthesis of an Optically Active Molecular Bevel Gear with Only Two Cogs on Each Wheel (SYNTHETIC ORGANIC CHEMISTRY-Fine Organic Synthesis)","authors":"K. Fuji*, T. Kawabata, Takahiro Oka","doi":"10.1016/S0040-4039(97)10848-6","DOIUrl":"https://doi.org/10.1016/S0040-4039(97)10848-6","url":null,"abstract":"","PeriodicalId":13086,"journal":{"name":"ICR annual report","volume":"58 1","pages":"36-37"},"PeriodicalIF":0.0,"publicationDate":"1998-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76190473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1998-03-01DOI: 10.1103/PHYSREVB.58.6442
K. Mibu, T. Nagahama, T. Ono, T. Shinjo
The magnetoresistance originating from magnetic structures with gradually rotating magnetic moments, like a Bloch wall, was investigated using soft-magnetic (NiFe)/hard-magnetic (CoSm) bilayers, whose magnetic structures were well characterized. The magnetoresistance was measured with an electric current in the film plane; the magnetoresistance in this geometry corresponds to that due to a current parallel to a Bloch wall. The main feature of the magnetoresistance curves was ruled by the anisotropic magnetoresistance. It was found that a giant magnetoresistance-type effect coexisted; the effect was very small in comparison with the anisotropic magnetoresistance effect.
{"title":"Magnetoresistance of Bloch-Wall-Type Magnetic Structures Induced in NiFe/CoSm Exchange-Spring Bilayers (SOLID STATE CHEMISTRY-Artificial Lattice Alloys)","authors":"K. Mibu, T. Nagahama, T. Ono, T. Shinjo","doi":"10.1103/PHYSREVB.58.6442","DOIUrl":"https://doi.org/10.1103/PHYSREVB.58.6442","url":null,"abstract":"The magnetoresistance originating from magnetic structures with gradually rotating magnetic moments, like a Bloch wall, was investigated using soft-magnetic (NiFe)/hard-magnetic (CoSm) bilayers, whose magnetic structures were well characterized. The magnetoresistance was measured with an electric current in the film plane; the magnetoresistance in this geometry corresponds to that due to a current parallel to a Bloch wall. The main feature of the magnetoresistance curves was ruled by the anisotropic magnetoresistance. It was found that a giant magnetoresistance-type effect coexisted; the effect was very small in comparison with the anisotropic magnetoresistance effect.","PeriodicalId":13086,"journal":{"name":"ICR annual report","volume":"29 1","pages":"16-17"},"PeriodicalIF":0.0,"publicationDate":"1998-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81174181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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