15790-86-0Relevant articles and documents
Direct Conversion of β,γ-Unsaturated Esters into Lactones Induced by TMS-I
Piva, Olivier
, p. 13687 - 13696 (1994)
β,γ-unsaturated esters readily prepared by photodeconjugation are converted in one step into butanolides by treatment with TMS-I.The reaction has been extended to the access to α-alkylidene lactones.
Conformational Study of SnCl4 Complexes of Aldehydes, α,β-Unsaturated Aldehydes, and Esters: Observation of Both s-Cis and s-Trans Isomers
Gung, Benjamin W.,Yanik, Mathew M.
, p. 947 - 951 (1996)
A variable-temperature NMR study shows that 2-methylpropanal (1a), ethyl 2-pentenoate (2), ethyl 4-methyl-2-pentenoate (3a), 2-pentenal (4), and 4-methyl-2-pentenal (5a) prefer the C-CH3 eclipsed conformations, rather than the CH-eclipsed form.The preference is enhanced in the presence of SnCl4.This is opposite to consideration based on steric interactions but is consistent with hyperconjugative interaction, in which the C-H bond is aligned with the ?*C=C orbital.Thus, the current result suggests that the C-H bond is a better donor than the C-C bond in hyperconjugation with electron-deficient ? orbital.On the other hand, 2-ethylbutanal (1b), ethyl 4-ethyl-2-hexenoate (3b), and 4-ethyl-2-hexenal (5b) prefer the CH-eclipsed form due to steric effects.At -50 deg C, the SnCl4 complexes of 3a and 3b show two distinct sets of vinyl protons in a ratio of ca. 10:1, which are assigned to the s-trans- and s-cis isomers, respectively.
The efficient synthesis of the optically active β-hydroxyl-γ- butyrolactone derivatives
Wang, Jin Xin,Li, Ying,Zhang, Chao Xin
, p. 1183 - 1187 (2003)
The optically active β-hydroxyl-γ-butyrolactones were synthesized from nonchiral starting material by employing reductive cleavage reaction, sharpless asymmetric epoxidation and dihydroxylation, and Lewis acid-catalysed cyclization as key steps. This strategy can be used to prepare many chiral β-hydroxyl-γ-butyrolactone analogues.
Iron carbonyl-promoted isomerization of olefin esters to their α,β-unsaturated esters: Methyl oleate and other examples
Shih, Kuo-Chen,Angelici, Robert J.
, p. 7784 - 7792 (1996)
Ultraviolet photolysis of stoichiometric amounts of methyl oleate and Fe(CO)5 in hexanes solvent at 0°C gives Fe(CO)3(η4-α,β-ester) in which the α,β-unsaturated ester isomer of methyl oleate is stabilized by η4-oxadiene π coordination of the olefin and ester carbonyl groups to the Fe(CO)3 unit. Treatment of the Fe(CO)3(η4-α,β-ester) with pyridine or CO liberates the free α,β-ester, methyl octadec-trans-2-enoate, in 70% yield. The Fe(CO)3 unit both catalyzes the olefin isomerization and stabilizes the α,β-unsaturated ester, which results in the formation of the α,β-ester in a yield far above that (3.5%) observed for simple catalyzed methyl oleate isomerization. The much smaller olefin esters, methyl 3-butenoate and ethyl 4-methyl-4-pentenoate, are isomerized under the same conditions to their α,β-unsaturated esters in 94 and 90% yields, respectively. The effects of reaction conditions on the yield, the use of Fe(CO)3(cis-cyclooctene)2 as a nonphotolytic catalyst, and the mechanism of this useful synthetic process are discussed.
PDC-mediated tandem oxidative-wittig olefination
Dhumaskar, Kashinath L.,Bhat, Chinmay,Tilve, Santosh G.
, p. 1501 - 1506 (2014)
A convenient tandem oxidative-Wittig olefination of a primary alcohols to α,β-unsaturated compounds using pyridinium dichromate (PDC) is described.
Copper-Catalyzed Aerobic Oxidative Azo-Ene Cyclization
Kim, Junsu,Lee, Da Hye,Kim, Jinho
supporting information, p. 4728 - 4733 (2021/09/09)
A copper-catalyzed aerobic oxidative azo-ene cyclization has been developed. The developed CuI/DMAP/O2 system efficiently facilitates the aerobic oxidation of ene-containing hydrazides to azo compounds, which undergo azo-ene cyclizations for the synthesis of oxazolidinones. In addition, the present approach enables the synthesis of lactams, as well as a nitroso-ene cyclization. Preliminary mechanistic studies revealed that two carbonyl groups were essential for the successful azo-ene cyclization and that a concerted mechanism might be plausible for this azo-ene cyclization. (Figure presented.).
Copper-Catalyzed Azide–Ynamide Cyclization to Generate α-Imino Copper Carbenes: Divergent and Enantioselective Access to Polycyclic N-Heterocycles
Chen, Yang-Bo,Deng, Chao,Liu, Rai-Shung,Liu, Xin,Luo, Chen,Wang, Ze-Shu,Ye, Long-Wu,Zhai, Tong-Yi,Zhang, Yi-Ping
supporting information, p. 17984 - 17990 (2020/08/21)
Here an efficient copper-catalyzed cascade cyclization of azide-ynamides via α-imino copper carbene intermediates is reported, representing the first generation of α-imino copper carbenes from alkynes. This protocol enables the practical and divergent synthesis of an array of polycyclic N-heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities. Moreover, an asymmetric azide–ynamide cyclization has been achieved with high enantioselectivities (up to 98:2 e.r.) by employing BOX-Cu complexes as chiral catalysts. Thus, this protocol constitutes the first example of an asymmetric azide–alkyne cyclization. The proposed mechanistic rationale for this cascade cyclization is further supported by theoretical calculations.
C-GLUCOSIDE DERIVATIVE CONTAINING FUSED PHENYL RING OR PHARMACEUTICALLY ACCEPTABLE SALT THEREOF, PROCESS FOR PREPARING SAME, AND PHARMACEUTICAL COMPOSITION COMPRISING SAME
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Paragraph 0418-0419, (2018/12/04)
The present disclosure relates to C-glycoside derivatives having a fused phenyl ring or pharmaceutical acceptable salts thereof, a method for preparing the same, a pharmaceutical composition comprising the same, a use thereof and a method for dual inhibition of SGLT1 and SGLT2 using the same. A novel compound of the present disclosure has a dual inhibitory activity against SGLT1 and SGLT2, thus being valuably used as a diabetes therapeutic agent.
Lewis Base Activation of Silyl Acetals: Iridium-Catalyzed Reductive Horner-Wadsworth-Emmons Olefination
Dakarapu, Udaya Sree,Bokka, Apparao,Asgari, Parham,Trog, Gabriela,Hua, Yuanda,Nguyen, Hiep H.,Rahman, Nawal,Jeon, Junha
supporting information, p. 5792 - 5795 (2015/12/11)
A Lewis base promoted deprotonative pronucleophile addition to silyl acetals has been developed and applied to the iridium-catalyzed reductive Horner-Wadsworth-Emmons (HWE) olefination of esters and the chemoselective reduction of the resulting enoates. Lewis base activation of silyl acetals generates putative pentacoordinate silicate acetals, which fragment into aldehydes, silanes, and alkoxides in situ. Subsequent deprotonative metalation of phosphonate esters followed by HWE with aldehydes furnishes enoates. This operationally convenient, mechanistically unique protocol converts the traditionally challenging aryl, alkenyl, and alkynyl esters to homologated enoates at room temperature within a single vessel.
Catalytic enantioselective dibromination of allylic alcohols
Hu, Dennis X.,Shibuya, Grant M.,Burns, Noah Z.
supporting information, p. 12960 - 12963 (2013/09/24)
A new dibromination reaction involving the combination of dibromomalonate as the bromonium source and a titanium bromide species as the bromide source has been developed. Enantioselective catalysis has been achieved through apparent ligand acceleration by a tartaric acid-derived diol.
