Enantioselective cyanosilylation of aldehydes catalyzed by novel camphor derived Schiff bases-titanium(IV) complexes
作者:Ewelina Błocka、Mariusz J. Bosiak、Mirosław Wełniak、Agnieszka Ludwiczak、Andrzej Wojtczak
DOI:10.1016/j.tetasy.2014.03.001
日期:2014.4
Five tridentate Schiff bases have been prepared from (1R,2S,3R,4S)-3-amino-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol and salicylaldehydes. X-ray structure investigation revealed differences in their molecular conformation, and their titanium(IV) complexes have been studied with NMR techniques. Among them the complex with the Schiffbase obtained from 2-hydroxy-3-isopropylbenzaldehyde, is the most selective
Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate
作者:Michael North、Marta Omedes-Pujol
DOI:10.3762/bjoc.6.119
日期:——
Propylene carbonate can be used as a green solvent for the asymmetricsynthesis of cyanohydrin trimethylsilyl ethers from aldehydes and trimethylsilyl cyanide catalysed by VO(salen)NCS, though reactions are slower in this solvent than the corresponding reactions carried out in dichloromethane. A mechanistic study has been undertaken, comparing the catalytic activity of VO(salen)NCS in propylene carbonate
CYANATION CATALYST AND METHOD FOR PRODUCING OPTICALLY ACTIVE CYANHYDRIN COMPOUND USING THE SAME
申请人:Ohkuma Takeshi
公开号:US20100029977A1
公开(公告)日:2010-02-04
The present invention can provide a cyanation catalyst represented by the general formula (I):
(in the formula (I), R
1
through R
4
are each an optionally substituted hydrocarbon group; R
1
and R
2
and/or R
3
and R
4
may form an optionally substituted carbon chain ring; R
5
through R
8
are each a hydrogen atom, or an optionally substituted hydrocarbon group; R
5
and R
6
and/or R
7
and R
8
may form an optionally substituted carbon chain ring; R
9
and R
10
are each a hydrogen atom, or an optionally substituted hydrocarbon group; W, X and Y each represent an optionally substituted binding chain; X and/or Y may be non-existent; M represents a metal or a metal ion; and ligands of M may each be located at any position).
The Asymmetric Addition of Trimethylsilyl Cyanide to Aldehydes Catalyzed by Chiral (Salen)Titanium Complexes
作者:Yuri N. Belokon'、Susana Caveda-Cepas、Brendan Green、Nicolai S. Ikonnikov、Viktor N. Khrustalev、Vladimir S. Larichev、Margarita A. Moscalenko、Michael North、Charles Orizu、Vitali I. Tararov、Michela Tasinazzo、Galina I. Timofeeva、Lidia V. Yashkina
DOI:10.1021/ja984197v
日期:1999.4.1
The use of chiral (salen)TiCl2 complexes to induce the asymmetricaddition of trimethylsilyl cyanide to aldehydes has been investigated. The complexes are catalytically active at substrate-to-catalyst ratios as high as 1000:1, and the optimal catalyst (2e) which is derived from (R,R)-1,2-diaminocyclohexane and 3,5-di-tert-butyl-2-hydroxybenzaldehyde produces trimethylsilyl ethers of cyanohydrins with
Asymmetric catalysis of carbon–carbon bond forming reactions using amino acid-derived C1-symmetrical salen ligands
作者:Yuri N. Belokon′、Jamie Hunt、Michael North
DOI:10.1016/j.tetasy.2008.11.037
日期:2008.12
Four amino acids (alanine, valine, phenylalanine and phenylglycine) have been converted into C1-symmetrical salen ligands and complexed to titanium, vanadium, copper and cobalt. The resulting complexes have been used as asymmetric catalysts for asymmetric cyanohydrin synthesis, asymmetric Strecker reactions, asymmetricsynthesis of α-methyl amino acids and asymmetric Darzens condensations. Satisfactory