246872-14-0Relevant academic research and scientific papers
NHC catalyzed enantioselective Coates-Claisen rearrangement: A rapid access to the dihydropyran core for oleuropein based secoiridoids
Vedachalam, Seenuvasan,Murugesh, Nithya,Chakraborty, Priyanka,Karvembu, Ramasamy,Liu, Xue-Wei
supporting information, p. 1832 - 1839 (2018/02/09)
We present the short synthesis of the suitably functionalized enantioselective dihydropyran core of secoiridoids using an N-heterocyclic carbene (NHC) catalyzed Coates-Claisen rearrangement mechanism. The key steps of the synthesis are (i) the highly enantioselective NHC catalyzed Coates-Claisen rearrangement for the dihydropyran core, (ii) the assembly of the target dihydropyran core structure of oleuropein from a highly diastereoselective exocyclic trans alkene, and (iii) the highly stereoselective assembly of a monoterpene elenolide core structure.
Short synthesis of phenylpropanoid glycosides calceolarioside-B and eutigoside-A
Khong, Duc Thinh,Judeh, Zaher M.A.
, p. 109 - 111 (2016/12/23)
A convenient 4-step synthesis of calceolarioside-B 1 and eutigoside-A 2 in high overall yield is described. The key step involved the regioselective, Me2SnCl2-catalyzed O-6 acylation of unprotected 2-phenylethyl-β-D-glucosides 5a–b with cinnamoyl chlorides 6a–b in excellent yields. Acylation at O-6 is selective with the acid chlorides used. This work serves as a model for the convenient synthesis of phenylpropanoid glycosides acylated at O-6.
Preparation of primary amines by the alkylation of O-sulfonyloximes of benzophenone derivatives with Grignard reagents
Tsutsui, Hironori,Ichikawa, Tomoko,Narasaka, Koichi
, p. 1869 - 1878 (2007/10/03)
Primary amines are prepared by the electrophilic amination of Grignard reagents with benzophenone O-sulfonyloxime derivatives. 4,4'- Bis(trifluoromethyl)benzophenone O-sulfonyloximes react with alkyl Grignard reagents in the presence of a catalytic amount of CuCN in tetrahydrofuran- hexamethylphosphoric triamide to give N-alkylimines, which are readily hydrolyzed to primary amines. 3,3',5,5'-Tetrakis(trifluoromethyl)benzophenone O-p-tolylsulfonyloxime is arylated to the corresponding N-arylimines with aryl Grignard reagents in ether-toluene, and hydrolysis of the resulting imines gives aniline derivatives.
Synthesis of verbascoside: A dihydroxyphenylethyl glycoside with diverse bioactivity
Duynstee, Howard I.,De Koning, Martijn C.,Ovaa, Huib,Van Der Marel, Gijs A.,Van Boom, Jacques H.
, p. 2623 - 2632 (2007/10/03)
TMSOTf-mediated condensation of ethyl 4,6-O-benzylidene-1-thio-β-D- glucopyranoside (2) with peracetylated α-L-rhamnopyranosyl trichloroacetimidate donor 3a resulted in the formation of orthoester 4, which, after acetylation, rearranged into ethyl 3-O-(α-L-rhamnopyranosyl)-l- thio-β-D-glucopyranoside derivative 6a. The latter compound was converted into the corresponding trichloroacetimidate donors 8a-b. An alternative approach to trichloroacetimidate 8c commenced with the iodonium ion mediated glycosidation of ethyl 2,3,4-tri-O-benzoyl-1-thio-α-L-rhamnopyranside (15) with 1,2:5,6-diisopropylidene-D-glucofuranose (16) to afford disaccharide 17, which was transformed into 8c in five steps. Condensation of 8a-c with 2- [3,4-di-(tert-butyldimethylsilyloxy)phenyl]ethanol (12) gave, after deacylation, key intermediate 14. Protecting-group manipulation of 14 and subsequent esterification of resulting 22 with 3,4-di-O-tert- butyldimethylsilylcaffeic acid (27) gave, after deprotection, verbascoside (1).
