1,4-Bis-Dipp/Mes-1,2,4-Triazolylidenes: Carbene Catalysts That Efficiently Overcome Steric Hindrance in the Redox Esterification of α- and β-Substituted α,β-Enals
作者:Veera Reddy Yatham、Wacharee Harnying、Darius Kootz、Jörg-M. Neudörfl、Nils E. Schlörer、Albrecht Berkessel
DOI:10.1021/jacs.5b11796
日期:2016.3.2
2,4-triazolium salts were synthesized and evaluated as (pre)catalysts in the redox esterification of various α- or β-substituted enals. In particular the 1,4-bis-Mes/Dipp-1,2,4-triazolylidenes overcome the above limitations and efficiently catalyze the redox esterification of a whole series of α/β-substituted enals hitherto not amenable to NHC-catalyzed transformations. The synthetic value of 1,4-bis-Mes/Dipp-1
N-Heterocyclic Carbene-Catalyzed Cyclization of Unsaturated Acyl Chlorides and Ketones
作者:Li-Tao Shen、Pan-Lin Shao、Song Ye
DOI:10.1002/adsc.201100178
日期:2011.8
synthesis of optically active trifluoromethyl dihydropyranones and spirocyclic oxindole-dihydropyranones has been realized by the chiral N-heterocyclic carbenes-catalyzed cyclization of α,β-unsaturated β-methylacyl chlorides with activated trifluoromethyl ketones or isatin derivatives.
hydrazine delivered a hexahydroindazole intermediate, which underwent N(2)‐substitution with various electrophiles (alkyl halides, acyl chlorides, phenyl isocyanate). The resulting N(2)‐substituted hexahydroindazoles could be reduced with LiBEt3H in THF to the target compounds. In addition, a N(2)‐thiobenzoyl and some N(2)‐carbamoyl derivatives as well as a N(1)‐substituted octahydroindazole were synthesized
Transition metal complex, catalyst for olefin polymerization, and process for producing olefin polymer with the same
申请人:——
公开号:US20040242410A1
公开(公告)日:2004-12-02
The present invention relates to a transition metal complex represented by the formula (I):
1
wherein M represents a Group 4 transition metal;
—Y— represents
(a): —C(R
1
)(R
20
)-A-,
(b): —C(R
1
)(R
20
)-A
1
(R
30
)—,
(c): —C(R
1
)=A
1
-, or
(d): —C(R
1
)=A
1
-A
2
-R
30
;
A represents a Group 16 element and A
1
and A
2
each represents a Group 15 element;
R
1
to R
9
, R
20
, and R
30
are the same or different and each represents an optionally substituted hydrocarbon group, etc.; and X
1
and X
2
are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted C
1-10
alkyl group, etc., and an intermediate product thereof, and a catalyst for olefin polymerization which comprises said transition metal complex as a component.
Tetrahydrocyclopent[b]indole-3-acetic acid, tetrahydrocarbazole-1-acetic acid and hexahydrocyclohept[b]-indole-6-acetic acid derivatives in which the carbon bearing alkyl, lower alkenyl or lower cycloalkyl are disclosed. The compounds are useful antiinflammatory agents and methods for their preparation and use are described.