4540-79-8Relevant academic research and scientific papers
OXANICKELACYCLOPENTEN-DERIVATE, EIN NEUER TYP VIELSEITIG VERWENDBARER SYNTHONE
Hoberg, Heinz,Schaefer, Dietmar,Burkhart, Georg
, p. C21 - C24 (1982)
Oxanickelacyclopentene derivatives (I), which can easily be prepared from carbon dioxide, alkynes and nickel(0) compounds, are shown to be versatile synthones.Some representative examples are given.
Divergent Synthetic Access to E- and Z-Stereodefined All-Carbon-Substituted Olefin Scaffolds: Application to Parallel Synthesis of (E)- and (Z)-Tamoxifens
Ashida, Yuichiro,Honda, Atsushi,Sato, Yuka,Nakatsuji, Hidefumi,Tanabe, Yoo
, p. 73 - 89 (2017/02/10)
A highly substrate-general synthesis of all-carbon-substituted E- and Z-stereodefined olefins is performed. The method comprises two sets of parallel and stereocomplementary preparations of (E)- and (Z)-α,β-unsaturated esters involving two robust and distinctive reactions: 1) stereocomplementary enol tosylations using readily available TsCl/diamine/(LiCl) base reagents, and 2) stereoretentive Negishi cross-coupling using the catalysts [Pd(dppe)Cl2] (for E) and [Pd(dppb)Cl2] (for Z). The present parallel approach is categorized as both type I (convergent approach: 16 examples, 56–87 % yield) and type II (divergent approach: 18 examples, 70–95 % yield). The obtained (E)- and (Z)-α,β-unsaturated ester scaffolds are successfully transformed into various E- and Z-stereodefined known and novel olefins (8×2 derivatization arrays). As a demonstration, application to the parallel synthesis of both (E)- and (Z)-tamoxifens, a representative motif of all-carbon-substituted olefins, is accomplished in a total of eight steps with an overall yield of 58 % (average 93 %) and 57 % (average 93 %), respectively.
Generation of ynolates via reductive lithiation using flow microreactors
Umezu, Satoshi,Yoshiiwa, Toshiya,Tokeshi, Manabu,Shindo, Mitsuru
, p. 1822 - 1825 (2014/03/21)
A new method has been developed for the generation and subsequent reaction of ynolates in a micro flow reactor system. This new procedure allowed for ynolates to be prepared at 0 C or ambient temperature within 1 min via a reductive lithiation reaction, whereas the corresponding batch processes generally require low temperature control and extended reaction times of up to 1 h. The resulting ynolates were applied to the olefination of carbonyl compounds, with the reactions reaching completion in a much shorter reaction time in the continuous flow reactor than the batch reactor. These results highlight the practical utility of the ynolate reaction, and represent the first reported example of the use of lithium naphthalenide in a flow microreactor, which would contribute to progress of the flash chemistry.
Key structural features of cis-cinnamic acid as an allelochemical
Abe, Masato,Nishikawa, Keisuke,Okuda, Katsuhiro,Shindo, Mitsuru,Fukuda, Hiroshi,Nakanishi, Kazunari,Tazawa, Yuta,Taniguchi, Tomoya,Park, So-Young,Hiradate, Syuntaro,Fujii, Yoshiharu
, p. 56 - 67,12 (2012/12/12)
1-O-cis-cinnamoyl-β-d-glucopyranose is one of the most potent allelochemicals isolated from Spiraea thunbergii Sieb. It is suggested that it derives its strong inhibitory activity from cis-cinnamic acid, which is crucial for phytotoxicity. It was synthesized to confirm its structure and bioactivity, and also a series of cis-cinnamic acid analogues were prepared to elucidate the key features of cis-cinnamic acid for lettuce root growth inhibition. The cis-cyclopropyl analogue showed potent inhibitory activity while the saturated and alkyne analogues proved to be inactive, demonstrating the importance of the cis-double bond. Moreover, the aromatic ring could not be replaced with a saturated ring. However, the 1,3-dienylcyclohexene analogue showed strong activity. These results suggest that the geometry of the C-C double bond between the carboxyl group and the aromatic ring is essential for potent inhibitory activity. In addition, using several light sources, the photostability of the cinnamic acid derivatives and the role of the C-C double bond were also investigated.
Rhodium-catalyzed and zinc(II)-triflate-promoted asymmetric hydrogenation of tetrasubstituted α,β-unsaturated ketones
Calvin, Joel R.,Frederick, Michael O.,Laird, Dana L. T.,Remacle, Jacob R.,May, Scott A.
, p. 1038 - 1041 (2012/04/10)
The asymmetric hydrogenation of tetrasubstituted α,β-unsaturated ketones has been accomplished using an in situ formed rhodium-Josiphos catalyst. The reaction is enhanced by addition of catalytic zinc(II) triflate, which significantly improves turnover fr
SYNTHESIS, MOLECULAR PROPERTIES AND PHARMACOLOGICAL ACTIVITY OF SOME p-SUBSTITUTED (E)- AND (Z)-α,β-DIMETHYLCINNAMIC ACIDS
Balsamo, Aldo,Crotti, Paolo,Macchia, Bruno,Macchia, Franco,Martinelli, Adriano,et al.
, p. 327 - 332 (2007/10/02)
A series of p-substituted (E)- and (Z)-α,β-dimethylcinnamic acids has been prepared and pharmacologically tested.The configurations of the acids prepared were determined from their NMR spectra.The UV spectra and the acid dissociation constants are reported.The collected data show that an extensive conjugation between the aryl and carboxy groups via the double bond does not exist, due to the steric hindrance of the α,β-dimethyl substitution on the cinnamic system.
