89996-94-1Relevant articles and documents
Highly Regio- A nd Enantioselective Hydrogenation of Conjugated α-Substituted Dienoic Acids
Liu, Xian,Liu, Song,Wang, Quanjun,Zhou, Gang,Yao, Lin,Ouyang, Qin,Jiang, Ru,Lan, Yu,Chen, Weiping
, p. 3149 - 3154 (2020/04/09)
Highly regio- A nd enantioselective hydrogenation of conjugated α-substituted dienoic acids was realized for the first time using Trifer-Rh complex, providing a straightforward method for the synthesis of chiral α-substituted ?,?′-unsaturated acids. DFT calculations revealed N+H-O hydrogen bonding interaction is formed to stabilize the transition state and the coordination of 4,5-double bond to Rh(III) center would facilitate the reductive elimination process. This hydrogenation provided a gram-scale synthesis of the precursor of sacubitril.
Microwave-assisted synthesis of the (E)-α-methylalkenoate framework from multifunctionalized allylic phosphonium salts
Meier, Lidiane,Ferreira, Misael,Sa, Marcus M.
experimental part, p. 179 - 186 (2012/07/14)
A convenient and general microwave-assisted method for the synthesis of stereochemically defined α-methylalkenoic acids and esters from allylic phosphonium salts in a basic aqueous medium is described. A selective preparation of acids or esters was dependent on the base (NaOH or NaHCO 3) employed in the reaction and could be achieved with good to excellent yields under mild conditions in the absence of hydrides and reducing agents.
A new 1,5- to 1,11-carbonyl transposition protocol involving ketene dithioacetal chemistry: An efficient polyene synthesis
Asokan,Shukla,Kumar,Ila,Junjappa
, p. 937 - 947 (2007/10/03)
An efficient strategy for alternative 1,5-, 1,7-, 1,9- and 1,11- carbonyl transposition has been developed via 1,2-reductive or alkylative addition to 5,5-bis(methylthio)-2,4-pentadienals 3a-b, 7,7-bis(methylthio)-2,4,6-heptatrienones 5,9,9-bis(methylthio)-2,4,6,8-nonatetraenones 8 and 11,11-bis(methylthio)-2,4,6,8,10-undecapentaenones 11 followed by BF3,Et2O induced methanolysis of the resulting carbinols to the corresponding polyene esters. The synthesis of the novel polyene aldehydes 3a-b, 7a-b, 10b and polyenones 5, 8, 11 precursors has also been described following iterative Vielsmeier-Haack reaction and aldol condensation.
Ruthenium complex-catalyzed coupling of vinyl halides with olefins
Mitsudo, Take-aki,Takagi, Masakazu,Zhang, Shi-Wei,Watanabe, Yoshihisa
, p. 405 - 414 (2007/10/02)
Ruthenium complexes such as Ru(COD)(COT) , catalyze the dehydrohalogenative coupling of vinyl halides with olefins to give the corresponding substituted dienes.Even the sp2-carbon-chloride bond of β-chlorostyrene is activated by ruthenium catalysts.
OXOKETENE DITHIOACETALS AS VERSATILE SYNTHONS FOR ALTERNATIVE 1,3 TO 1,11 CARBONYL TRANSPOSITIONS: A NEW POLYENE SYNTHESIS
Chandrasekharam, Malapaka,Asokan, Chitoorthekkathil V.,Ila, Hiriyakkanavar,Junjappa, Hiriyakkanavar
, p. 1763 - 1766 (2007/10/02)
A model strategy for 1,7 to 1,11 carbonyl transpositions involving 1,2 addition of sodium borohydride or Grignard reagents to polyenyl oxoketene dithioacetals 8 obtained by condensation of bis(methylthio)polyenals 1-3 with active methylene ketones, followed by borontrifluoride etherate catalyzed methanolysis of the resulting polyenyl carbinol acetals 9 to give 1,n transposed polyene esters 10 has been described.
A STEREOSELECTIVE SYNTHESIS OF (Z)-α,β-DISUBSTITUTED ACRYLATES
Shimagaki, Masayuki,Shiokawa, Manabu,Sugai, Kazunori,Teranaka, Tomoko,Nakata, Tadashi,Oishi, Takeshi
, p. 659 - 662 (2007/10/02)
A new route for (Z)-α,β-disubstituted acrylate is described which is made up of 1) stereoselective reduction of ketones 3 and 2) conversion of the resulting syn-2 into (Z)-1.
SYNTHESE STEREOSELECTIVE D'ESTERS α,β-ETHYLENIQUES α-METHYLES Z OU E PAR LA REACTION DE WITTIG-HORNER A PARTIR DE PHOSPHONATES OU D'OXYDES DE PHOSPHINE
Etemad-Moghadam, Guita,Seyden-Penne, Jacqueline
, p. 5153 - 5166 (2007/10/02)
The reaction of α-branched aldehydes with diethyl 1-carbomethoxyethyl phosphonate 1b in THF/nBuLi at low temperature leads stereoselectively to Z α-methyl α,β-unsaturated esters.From a linear aldehyde, the reaction is less stereoselective, while from α,β-unsaturated ones, the E isomers are predominantly formed in good yields.From diphenyl 1-carbomethoxyethyl phosphine oxide 2b, E α-methyl α,β-unsaturated esters are stereoselectively formed either in DMF/tBuOK or in phase transfer conditions, whatever the starting aldehyde is, also in good yields.This reagent can thus advantageously replace the corresponding P-ylid.In all cases, the reaction conditions are determined so that by-products formation is minimized.
NOUVEAUX REACTIFS PRECURSEURS D' OLEFINES TRISUBSTITUEES E : LES OXYDES DE PHOSPHINE.
Seyden-Penne, J.,Etemad-Moghadam, G.,Bottin-Strzalko, T.,Simonnin, M.-P.
, p. 179 - 182 (2007/10/02)
From NMR data, phosphine oxides 4 show similarity to Pylids and give E trisubstituted olefins from saturated and unsaturated aldehydes.
