186895-72-7Relevant academic research and scientific papers
Direct, enantioselective α-alkylation of aldehydes using simple olefins
Capacci, Andrew G.,Malinowski, Justin T.,McAlpine, Neil J.,Kuhne, Jerome,Macmillan, David W. C.
, p. 1073 - 1077 (2018/08/17)
Although the α-alkylation of ketones has already been established, the analogous reaction using aldehyde substrates has proven surprisingly elusive. Despite the structural similarities between the two classes of compounds, the sensitivity and unique reactivity of the aldehyde functionality has typically required activated substrates or specialized additives. Here, we show that the synergistic merger of three catalytic processes—photoredox, enamine and hydrogen-atom transfer (HAT) catalysis—enables an enantioselective α-aldehyde alkylation reaction that employs simple olefins as coupling partners. Chiral imidazolidinones or prolinols, in combination with a thiophenol, iridium photoredox catalyst and visible light, have been successfully used in a triple catalytic process that is temporally sequenced to deliver a new hydrogen and electron-borrowing mechanism. This multicatalytic process enables both intra-and intermolecular aldehyde α-methylene coupling with olefins to construct both cyclic and acyclic products, respectively. With respect to atom and step-economy ideals, this stereoselective process allows the production of high-value molecules from feedstock chemicals in one step while consuming only photons.
Reversible 1,3-anti/syn-stereochemical courses in copper-catalyzed γ-selective allyl-alkyl coupling between chiral allylic phosphates and alkylboranes
Nagao, Kazunori,Yokobori, Umi,Makida, Yusuke,Ohmiya, Hirohisa,Sawamura, Masaya
supporting information; scheme or table, p. 8982 - 8987 (2012/07/02)
The stereochemical courses of the copper-catalyzed allyl-alkyl coupling between enantioenriched chiral allylic phosphates and alkylboranes were switchable between 1,3-anti and 1,3-syn selectivities by the choice of solvents and achiral alkoxide bases with different steric demands. The reactions with γ-silylated allylic phosphates allow efficient synthesis of enantioenriched chiral allylsilanes with tertiary or quaternary carbon stereogenic centers. Cyclic and acyclic bimodal participation of alkoxyborane species in an organocopper addition-elimination sequence is proposed to account for the phenomenon of the anti/syn-stereochemical reversal.
An asymmetric hydroformylation catalyst that delivers branched aldehydes from alkyl alkenes
Noonan, Gary M.,Fuentes, Jose A.,Cobley, Christopher J.,Clarke, Matthew L.
supporting information; experimental part, p. 2477 - 2480 (2012/04/18)
Surprising selectivity: The first enantioselective hydroformylations of simple alkenes of type RCH2CH=CH2 to preferentially deliver the branched aldehyde product have been discovered using a new chiral ligand, named bobphos (see scheme). Established ligands are unselective in this reaction or show a slight preference towards the linear aldehyde. Copyright
Identification of a valuable kinetic process in copper-catalyzed asymmetric allylic alkylation
Langlois, Jean-Baptiste,Alexakis, Alexandre
supporting information; experimental part, p. 1877 - 1881 (2011/04/16)
Copper bottomed: The application of a previously described process of dynamic kinetic asymmetric transformation to acyclic substrates allowed the identification of a relevant kinetic process in the title reaction (see scheme; CuTC= copper(I) thiophencarboxylate, Naphth= naphthyl). The optimization of the reaction conditions and generality of the method, as well as mechanistic considerations are disclosed.
Efficient and selective synthesis of 6,7-dehydrostipiamide via Zr-catalyzed asymmetric carboalumination and Pd-catalyzed cross-coupling of organozincs
Zeng, Xingzhong,Zeng, Fanxing,Negishi, Ei-Ichi
, p. 3245 - 3248 (2007/10/03)
(Chemical Equation Presented) 6,7-Dehydrostipiamide has been synthesized in 23% yield in 15 steps in the longest linear sequence through the application of the Zr-catalyzed asymmetric carboalumination and the Pd-catalyzed organozinc cross-coupling in addi
Synthesis of a C-9 to C-18 building block of the phenalamides
Hoffmann, Reinhard W.,Haeberlin, Eckart,Rohde, Thorsten
, p. 207 - 212 (2007/10/03)
In the context of a synthesis of phenalamide A2, the C-9 to C-18 building block 6 was synthesized. The stereogenic centers were generated by alkylation of an Evans oxazolidinone 12 and by a crotylboration reaction using the enantiomerically pure (E)-α-chlorocrotylboronate (4).
Total synthesis of phenalamide A2
Hoffmann, Reinhard W.,Rohde, Thorsten,Haeberlin, Eckart,Sch?fer, Frank
, p. 1713 - 1715 (2008/02/11)
(formula presented) Phenalamide A2 (1b) has been synthesized for the first time. The synthesis features the homologation of aldehyde 5 to trienal 3 with the new conjunctive reagent 6 and the formation of amide 14 with the functionalized Horner-
Total synthesis of stipiamide and designed polyenes as new agents for the reversal of multidrug resistance
Andrus, Merritt B.,Lepore, Salvatore D.,Turner, Timothy M.
, p. 12159 - 12169 (2007/10/03)
The synthesis of (-)-stipiamide (1) is reported together with the designed enynes 2 (6,7-dehydrostipiamide) and 3 that are now shown to reverse the multidrug resistance (MDR) of human breast cancer cells (MCF-7adrR). Stipiamide was assembled using a Still
