Thermolytic rearrangements of 1,1-cyclopropanedimethanol disulfonates: cyclopropylcarbinyl cations revisited
摘要:
1,1-Cyclopropanedimethanol dimethanesulfonate (1a) and the corresponding ditosylate lb underwent thermal rearrangement at 110-140-degrees-C after melting. Short reaction time resulted in the formation of mixtures containing 1-(sulfonyloxy)cyclobutanemethanol sulfonates 5a,b (major), starting material, and 2-methylene-1,4-butanediol disulfonates 6a,b. Longer reaction times afforded complete conversion to disulfonates 6a,b, isolated in 49 and 62 % yield, respectively. These reactions are postulated to proceed via initial carbocation formation, presumably interconverting bicylobutonium and cyclopropylcarbinyl cations, which exist as ion pairs in the melt. Crossover experiments with dimesylate la and ditosylate lb offer support for the presence of ion pairs in the melt: internal return competed with external trapping of the intermediate cations. Reaction of la and 2-methylene-1,4-butanediol ditosylate (6b) gave a mixture in which 2-methylene-1,4-butanediol 1-mesylate 4-tosylate (8) predominated over the isomeric 4-mesylate 1-tosylate 7 by a 5:1 ratio. Crossover experiments with 6a and 6b indicated that partial allylic substitution was occurring for the open-chain products under the thermolysis conditions. Reaction of la with excess tetrabutylammonium tosylate at 114-15-degrees-C afforded mixed 1-(sulfonyloxy)cyclobutanemethanol sulfonates and 2-methylene-1,4-butanediol disulfonates formed competitively by internal return and tosylate interception. Acetolysis of la at 42-43-degrees-C afforded predominately products of internal return early on the reaction profile. Longer reaction times afforded predominately monoacetates while reactions run at 108-10-degrees-C afforded substantial amounts of diacetates. Acetolysis of 1-acetoxycyclobutanemethanol mesylate (12a) resulted in the substitution of the mesyloxy group with substantial rearrangement.
Discovery and Elucidation of Counteranion Dependence in Photoredox Catalysis
作者:Elliot P. Farney、Steven J. Chapman、Wesley B. Swords、Marco D. Torelli、Robert J. Hamers、Tehshik P. Yoon
DOI:10.1021/jacs.9b01885
日期:2019.4.17
past decade, there has been a renewed interest in the use of transition metal polypyridyl complexes as photoredoxcatalysts for a variety of innovative synthetic applications. Many derivatives of these complexes are known, and the effect of ligand modifications on their efficacy as photoredoxcatalysts has been the subject of extensive, systematic investigation. However, the influence of the photocatalyst
POSITIVE RESIST COMPOSITION AND PATTERNING PROCESS
申请人:NISHI Tsunehiro
公开号:US20100062374A1
公开(公告)日:2010-03-11
A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising recurring units containing a non-leaving hydroxyl group represented by formula (1) wherein R
1
is H, methyl or trifluoromethyl, X is a single bond or methylene, m is 1 or 2, and the hydroxyl group attaches to a secondary carbon atom. The composition is improved in resolution when processed by lithography.
NOVEL PHOTOACID GENERATOR, RESIST COMPOSITION, AND PATTERNING PROCESS
申请人:Ohsawa Youichi
公开号:US20090246694A1
公开(公告)日:2009-10-01
Photoacid generators generate sulfonic acids of formula (
1
a) upon exposure to high-energy radiation.
ROC(═O)R
1
—COOCH
2
CF
2
SO
3
−
H
+
(1a)
RO is OH or C
1
-C
20
organoxy, R
1
is a divalent C
1
-C
20
aliphatic group or forms a cyclic structure with RO. The photoacid generators are compatible with resins and can control acid diffusion and are thus suited for use in chemically amplified resist compositions.
Pd2+⋯O3SR− interaction encourages anion encapsulation of a quadruply-stranded Pd complex to achieve chirality or high solubility
作者:Ryo Sekiya、Reiko Kuroda
DOI:10.1039/c1cc14982b
日期:——
Pd2+â¯O3SRâ and CHâ¯O3SRâ interactions were found to play a crucial role in the encapsulation of organic sulfonates in a quadruply-stranded complex of Pd2L4-type. We have successfully employed this feature to achieve chirality induction by complexation with chiral guests as well as solubility increase by dendronization.
Anion-Directed Formation and Degradation of an Interlocked Metallohelicate
作者:Ryo Sekiya、Morihiko Fukuda、Reiko Kuroda
DOI:10.1021/ja303634u
日期:2012.7.4
architecture consisting of twomechanicallyinterlocked monomers, [Pd(2)L(4)](4+) (1(4+)). 2(8+) has three internal cavities, each of which encapsulates one NO(3)(-) ion (1:3 host-guest complex, 2⊃(NO(3)|NO(3)|NO(3))(5+)) and is characterized by unusual thermodynamic stability. However, both the driving force for the dimerization and the origin of the thermodynamic stability remain unclear. To clarify these issues