5075-59-2Relevant articles and documents
Rare-Earth Catalyzed C?H Bond Alumination of Terminal Alkynes
Kanbur, Uddhav,Sadow, Aaron D.
, p. 5479 - 5493 (2020/04/15)
Organoaluminum reagents’ application in catalytic C?H bond functionalization is limited by competitive side reactions, such as carboalumination and hydroalumination. Herein, rare-earth tetramethylaluminate complexes are shown to catalyze the exclusive C?H bond metalation of terminal alkynes with the commodity reagents trimethyl-, triethyl-, and triisobutylaluminum. Kinetic experiments probing alkyl-group exchange between rare-earth aluminates and trialkylaluminum, C?H bond metalation of alkynes, and catalytic conversions reveal distinct pathways of catalytic aluminations with triethylaluminum versus trimethylaluminum. Most significantly, kinetic data point to reversible formation of a unique [Ln](AlR4)2?AlR3 adduct, followed by turnover-limiting alkyne metalation. That is, C?H bond activation occurs from a more associated organometallic species, rather than the expected coordinatively unsaturated species. These mechanistic conclusions allude to a new general strategy for catalytic C?H bond alumination that make use of highly electrophilic metal catalysts.
Lewis base directed cycloaddition reactions of 2-pyrones and alkynylaluminum reagents
Crepin, Damien F.,Harrity, Joseph P. A.
supporting information, p. 4222 - 4225 (2013/09/12)
In situ generated alkynylaluminum reagents have been utilized in a [4 + 2] cycloaddition with 2-pyrones bearing a Lewis basic donor. The reactions proceed at or below room temperature and with complete regiocontrol. This one-pot method affords diversely s
Reaction of Organoaluminium Reagents with Cyclopropylmethyl Acetates and 2-Vinylcyclopropane-1,1-dicarboxylate Esters
Hiyama, Tamejiro,Morizawa, Yoshitomi,Yamamoto, Hajime,Nozaki, Hitosi
, p. 2151 - 2160 (2007/10/02)
Ring-opening alkylation of cyclopropylmethyl acetates was studied.The acetoxyl group of 7-(1-acetoxyheptyl)norcarane is substituted by the alkyl group upon treatment with trialkylaluminium, but alkylation of trans-1-(1-acetoxyethyl)-2-phenylcyclopropane with trialkylaluminium gives rise to trans-5-phenyl-2-alkenes.The reaction of (1S,2S)-2-phenylcyclopropylmethyl acetate with trimethylaluminium resulted in the complete loss of optical activity to give racemic 4-phenyl-1-pentene.Alkylation of trans-1-(1-acetoxy-3-phenylpropyl)-2-vinylcyclopropane with trialkylaluminium proceeds under regioselective ring-opening to give 3-alkylated trans-8-phenyl-1,5-octadiene (selectivity 73-83percent).The regio- and stereochemistry of homoconjugate addition to activated vinylcyclopropanes having a doubly carbonyl substituted ring carbon was studied.Trialkylaluminium on addition to diethyl 2-vinylcyclopropane-1,1-dicarboxylate in a 1,5-manner afford diethyl (2-alkyl-3-butenyl)propanedioate (over 96percent selectivity).In contrast, the reaction of this cyclopropane with tetraalkylaluminiumlithium takes place in a 1.7-manner to give diethyl (trans-4-alkyl-2-butenyl)propanedioate with 88-92percent selectivity.Clean regiocontrol of the reaction is observed in the methylation of ethyl exo-6-(trans-1-propenyl)-2-oxobicyclo(3.1.0>hexane-1-carboxylate with trimethylaluminium or tetramethyl aluminiumlithium.Alkylation with trimethylaluminium proceeds with 86percent inversion of the configuration at C(6) of the substrate, affording (2R*,3R*)-2-ethoxycarbonyl-3-cyclopentanone which is transformed into neonepetalactone.
