4866-54-0Relevant academic research and scientific papers
Mild Ring-Opening 1,3-Hydroborations of Non-Activated Cyclopropanes
Wang, Di,Xue, Xiao-Song,Houk, Kendall N.,Shi, Zhuangzhi
supporting information, p. 16861 - 16865 (2018/11/27)
The Brown hydroboration reaction, first reported in 1957, is the addition of B?H across an olefin in an anti-Markovnikov fashion. Here, we solved a long-standing problem on mild 1,3-hydroborations of non-activated cyclopropanes. A three-component system including cyclopropanes, boron halides, and hydrosilanes has been developed for borylative ring-opening of cyclopropanes following the anti-Markovnikov rule, under mild reaction conditions. Density functional theory (M06-2X) calculations show that the preferred pathway involves a cationic boron intermediate which is quenched by hydride transfer from the silane.
Cyclopropanation of alkenes with CH2I2/Et3Al by the phase-vanishing method based on fluorous phase screen
Matsubara, Hiroshi,Tsukida, Masaaki,Yasuda, Shinji,Ryu, Ilhyong
scheme or table, p. 951 - 954 (2009/04/04)
Phase-vanishing (PV) method using perfluorohexanes as a screen phase was applied to cyclopropanation reactions with CH2I2/Et2Zn and CH2I2/Et3Al. When Et3Al was used as a carbenoid generator, the reaction proceeded smoothly and desired cyclopropane derivatives were obtained in high yield. The PV cyclopropanation took 2 or 3 days to complete, however, reduction of reaction time by a factor of 2-3 was also achieved by vigorous stirring after the bottom CH2I2 layer disappeared.
Lanthanum metal-assisted cyclopropanation of alkenes with gem-dihaloalkanes
Nishiyama, Yutaka,Tanimizu, Hana,Tomita, Tsuyoshi
, p. 6405 - 6407 (2008/02/12)
It was confirmed that lanthanum metal was an efficient reagent for the reductive dehalogenation of gem-dihaloalkanes. When gem-dihaloalkanes were allowed to react with lanthanum metal in the presence of alkenes, cyclopropanation of the alkenes occurred under mild conditions giving the corresponding cyclopropanes in moderate to good yields.
Processing of cyclopropylarenes by toluene dioxygenase: Isolation and absolute configuration of metabolites
Finn, Kevin J.,Rochon, Lena,Hudlicky, Tomas
, p. 3606 - 3613 (2007/10/03)
Several arenes possessing a cyclopropyl substituent were subjected to enzymatic oxidation with toluene dioxygenase. The absolute configuration of metabolites was established by chemical means.
Highly diastereoselective hydrostannylation of allyl and homoallyl alcohols with dibutyl(trifluoromethanesulfoxy)stannane
Miura, Katsukiyo,Wang, Di,Hosomi, Akira
, p. 9366 - 9367 (2007/10/03)
Dibutyl(trifluoromethanesulfoxy)stannane (Bu2Sn(OTf)H, 1a) was found to be very valuable for highly diastereoselective homolytic hydrostannylation of allyl and homoallyl alcohols. α,β-Disubstituted allyl alcohols and α,γ-disubstituted homoallyl alcohols were converted into γ- and δ-stannylated alcohols with high 1,2-syn and 1,3-syn diastereoselectivity, respectively. The origin of the stereochemical outcomes can be rationalized by conformational fixation of the intermediary β-stannylalkyl radical by coordination of the hydroxy group to the Lewis acidic tin center. Copyright
A Novel Class of Tunable Zinc Reagents (RXZnCH2Y) for Efficient Cyclopropanation of Olefins
Lorenz, Jon C.,Long, Jiang,Yang, Zhiqiang,Xue, Song,Xie, Yinong,Shi, Yian
, p. 327 - 334 (2007/10/03)
A class of zinc reagents (RXZnCH2Y) generated with an appropriate organozinc is very effective for the cyclopropanation of olefins. The reactivity and selectivity of these reagents can be regulated by tuning the electronic and steric nature of the RX group on Zn. A reasonable level of enantioselectivity was obtained for the cyclopropanation of unfunctionalized olefins when a chiral (iodomethyl)zinc species was used, providing a valuable approach for the asymmetric cyclopropanation of unfunctionalized olefins.
A one-pot access to cyclopropanes from allylic ethers via hydrozirconation-deoxygenative ring formation
Gandon, Vincent,Szymoniak, Jan
, p. 1308 - 1309 (2007/10/03)
A synthetic method for the direct transformation of allylic ethers into mono-, di- and trisubstituted cyclopropanes is presented.
Oxidation of aryl- and diarylcyclopropanes in a pentasil zeolite: Ring opening with deprotonation or net hydrogen migration
Herbertz, Torsten,Lakkaraju, Prasad Sreeramachandra,Blume, Florian,Blume, Matthias,Roth, Heinz Dieter
, p. 467 - 472 (2007/10/03)
Incorporation of trans-1,2-diphenylcyclopropane (1) and its 3,3-D2- isotopomer into the channels of a redox-active pentasil zeolite (Na-ZSM-5) resulted in the formation of exo,exo-1,3-diphenylallyl radical (2.) and its 2-D1 isotopomer, respectively. This conversion requires oxidation, ring opening, and deprotonation, in an unspecified sequence. The allyl radical 2. is also formed upon incorporation of trans-1,3-diphenylpropene (3). A comparison with the solution photochemistry, in the presence or absence of added base, shows the conversion of 1 into 2. to be a zeolite-specific reaction. Incorporation of arylcyclopropanes 9 (R = H, OCH3) into ZSM-5 generated trans-propenylbenzene radical cations 10.+ (R = H, OCH3); the 2,2-D2 isotopomer of 9 (R = OCH3) gave rise to three different isotopomers of 10.+) (R = OCH3).
Exploring new reactive species for cyclopropanation
Yang, Zhiqiang,Lorenz, Jon C.,Shi, Yian
, p. 8621 - 8624 (2007/10/03)
An organozinc species RXZnCH2I generated by reacting Zn(CH2I)2 with RXH was found to be an efficient reagent for the cyclopropanation of olefins at room temperature. A 50.7% ee was obtained for the cyclopropanation of trans-β-methylstyrene when a chiral alcohol was used.
