5076-19-7Relevant articles and documents
Study of the addition of monoalkylphosphonic acids onto trialkyl-substituted epoxides
Derouet,Cauret,Brosse
, p. 3767 - 3774 (2001)
The addition of 2-chloroethylphosphonic acid (or ethephon), a well-known stimulating molecule for the production of latex by Hevea brasiliensis, onto 2,3-epoxy-2-methylbutane was investigated to enhance the understandings on the addition mechanisms of reagents of alkylphosphonic acid type onto trialkyl-substituted epoxides. It was demonstrated that the addition occurs according to a three-step mechanism including a rapid nucleophilic attack of the phosphorated anion on the most alkyl-substituted carbon of the oxirane, followed by formation of a dioxaphospholane structure with release of water, and finally a hydrolytic cleavage of the dioxaphospholane cycle to generate the regioisomer 1:1 adduct where the phosphorated group is on the less alkyl-substituted carbon of the initial oxirane.
ESR Evudence for Localized Forms of C - C Ring-Opened Oxirane Radical Cations
Qin, Xue-Zhi,Snow, Larry D.,Williams, Ffrancon
, p. 3602 - 3606 (1985)
Localized forms of the C...C ring-opened oxirane and methyl-substituted oxirane radical cations have been detected by ESR spectroscopy following γ-irradiation of solid solutions of the parent compounds in the CFCl2CF2Cl matrix.For oxirane, 1,2-dimethyloxirane, and tetramethyloxirane, he localized forms possess the RCH2., RCHMe., and the RCMe2. radical centers, respectively.In the unsymmetrically substituted methyloxiranes, the radical center is localized at the oxirane carbon with the least number of methyl groups.The temperature needed to bring about the formation of of the localized species increases with methyl substitution at the localized radical center, the oxirane and methoxirane species being formed during irradiation at 77 K while the tetramethyloxirane species is produced subsequently from the delocalized planar form of the of ring-opened cation at 105-110 K.In contrast, only the delocalized forms of the oxirane cations have been observed in CFCl3, CF3CCl3, and CCl4, even at much higher temperatures (145-215 K) close to the softening points of these matrices.The possible structures of the localized forms of the oxirane radical cations are discussed, the two most reasonable models being either an orthogonal structure with noninteracting radical and carbocation centers or a similar species in which the carbocation center is complexed with the solvent or combined with a chloride ion.Despite the lack of ESR and other evidence for some type of solvent haloen participation in the localized structure, the latter model cannot be ruled out at present.
Regioselective Organocatalytic Formation of Carbamates from Substituted Cyclic Carbonates
Sope?a, Sergio,Laserna, Victor,Guo, Wusheng,Martin, Eddy,Escudero-Adán, Eduardo C.,Kleij, Arjan W.
supporting information, p. 2172 - 2178 (2016/07/16)
A highly regioselective catalytic approach has been developed towards carbamates derived from cyclic organic carbonates by reaction of the latter with amine reagents under organocatalytic control. For various combinations of carbonate and amine substrates, an organocatalyst (TBD: 1,5,7-triazabicyclo[4.4.0]dec-5-ene) was used to increase the reaction kinetics while exerting excellent regioselective control. The current method is the first general approach towards the control over the regioselectivity of this reaction using a wide variety of easily accessed substituted organic carbonates. (Figure presented.) .
(4 S,5 S)-2,2,4-Triethyl-5-methyl-1,3-dioxolane: A new volatile released by a triatomine bug
Unelius,Bohman,Lorenzo,Troeger,Franke,Francke
supporting information; experimental part, p. 5601 - 5603 (2011/03/20)
Adults of the triatomine bug Triatoma brasiliensis release 2,2,4-triethyl-5-methyl-1,3-dioxolane (1) as a mixture of the (4S,5S)- and (4R,5R)-enantiomers in a ratio of 4:1. Among the volatile acetals identified from insects so far, this is the first example resulting from an intermolecular condensation of a carbonyl moiety and a diol substructure.