137482-91-8Relevant academic research and scientific papers
Highly regio- and stereoselective rearrangement of epoxides to aldehydes catalyzed by high-valent metalloporphyrin complex, Cr(TPP)OTf
Suda, Kohji,Kikkawa, Taketoshi,Nakajima, Shin-Ichiro,Takanami, Toshikatsu
, p. 9554 - 9555 (2004)
Chromium(III) tetraphenylporphyrin triflate, Cr(TPP)OTf, works as an efficient and characteristic Lewis acid catalyst in the regio- and stereoselective rearrangement of epoxides to aldehydes. This Cr(TPP)OTf-catalyzed reaction is an operationally simple a
Enantioselective Desymmetrization of 1,3-Diols by a Chiral DMAP Derivative
Mandai, Hiroki,Ashihara, Kosuke,Mitsudo, Koichi,Suga, Seiji
supporting information, p. 1360 - 1363 (2018/10/21)
We developed an enantioselective desymmetrization of 1,3-diols by a chiral N,N-dimethyl-4-aminopyridine (DMAP) derivative containing a 1,1-binaphthyl with tert-alcohol units. The reactions required only 0.1 mol% of catalyst and showed moderate to high chemoselectivity (monoacylation vs. diacylation) and enantioselectivity (14 examples, up to 95:5 er). Several control experiments revealed that diol units in both the substrate and the catalyst are important to achieve high enantioselectivity.
Chiral phosphoric acid catalyzed highly enantioselective desymmetrization of 2-substituted and 2,2-disubstituted 1,3-diols via oxidative cleavage of benzylidene acetals
Meng, Shan-Shui,Liang, Yong,Cao, Kou-Sen,Zou, Lufeng,Lin, Xing-Bang,Yang, Hui,Houk,Zheng, Wen-Hua
, p. 12249 - 12252 (2014/10/16)
A highly enantioselective catalytic protocol for the desymmetrization of a wide variety of 2-substituted and 2,2-disubstituted 1,3-diols is reported. This reaction proceeds through the formation of an "ortho ester" intermediate via oxidation of 1,3-diol benzylidene acetal by dimethyldioxirane (DMDO) and the subsequent proton transfer catalyzed by chiral phosphoric acid (CPA). The mechanism and origins of enantioselectivity of this reaction are identified using DFT calculations. The oxidation by DMDO is rate-determining, and the phosphoric acid significantly accelerates the proton transfer; the attractive interactions between the benzylidene part of the substrate and the 2,4,6-triisopropyl group of CPA are the key to high enantioselectivity.
Catalytic enantioselective intermolecular desymmetrization of 3-substituted oxetanes
Wang, Zhaobin,Chen, Zhilong,Sun, Jianwei
supporting information, p. 6685 - 6688 (2013/07/26)
Wring it out: The title reaction proceeds in the presence of chiral Bronsted acid catalysts. This efficient ring-opening process features low catalyst loading, mild reaction conditions, broad functional group compatibility, high enantioselectivity, and the capability to generate chiral quaternary centers. The highly functionalized desymmetrization products are versatile chiral building blocks in organic synthesis. Copyright
Organoaluminum-catalyzed rearrangement of epoxides a facile route to the synthesis of optically active β-siloxy aldehydes
Maruoka, Keiji,Ooi, Takashi,Nagahara, Shigeru,Yamamoto, Hisashi
, p. 6983 - 6998 (2007/10/02)
A new, stereocontrolled rearrangement of epoxy silyl ethers leading to β-siloxy aldehydes has been effected with stoichiometric use of exceptionally bulky, oxygenophilic methylaluminum bis(4-bromo-2,6-di-trert-butylphenoxide) (MABR) under mild conditions. Used in combination with the Sharpless asymmetric epoxidation of allylic alcohols, this rearrangement represents a new approach to the synthesis of various optically active β-hydroxy aldehydes, useful intermediates in natural product synthesis. The modified organoaluminum reagent, MABR is also applicable to the transformation of a variety of simple epoxides to carbonyl compounds with high efficiency and selectivity. Further, the catalytic version for the rearrangement of epoxy silyl ethers as well as simple epoxides has been newly devised. The scope and limitation of this catalytic method has been clarified with various epoxy substrates.
