- Stereoselective synthesis of chiral 3-aryl-1-alkynes from bromoallenes and heterocuprates
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The synthesis of chiral 3-aryl-1-alkynes 3 via cross-coupling of 3-alkyl- and 3,3-dialkyl-1-bromo-1,2-dienes 1 and arylbromocuprates (RCuBr)MgBr-LiBr 2 was examined. With phenylcopper reagents and its para-substituted derivatives, as well as with 2-naphth
- Caporusso, Anna Maria,Zampieri, Alessia,Aronica, Laura Antonella,Banti, Donatella
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- One post stereoselective synthesis of chiral αω-diynes from bromoallenes and organobis(heterocuprates)
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Organobis(heterocuprates), 7 and 8, have been prepared reacting in situ 1,4-dilithiobutane and di-Grignard reagents, obtained from 1,4-dibromobutane and 1,4-dibromobenzene, respectively, with CuSPh and LiCuBr2. The cross-coupling reaction of these di-cuprate reagents with 3-alkyl and 3,3-dialkyl 1-bromo-1,2-dienes (1) provides a general method for selective synthesis of 1,9-decadiynes (5) and 1,4-bis(2-propynyl)benzenes (6), characterized by two identical chiral centres in the α position to the triple bonds. The high 1,3-anti stereoselectivity of the coupling process allows us to obtain enantiomerically enriched α,ω-diynes 5 and 6 starting from optically active allenic substrates 1.
- Caporusso, Anna Maria,Aronica, Laura Antonella,Geri, Roberto,Gori, Marco
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p. 109 - 118
(2007/10/03)
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- REACTIONS OF 3-ALKYL- AND 3,3-DIALKYL-1-BROMOALLENES WITH ORGANOCUPRATES: EFFECTS OF THE NATURE OF THE CUPRATE REAGENT ON THE REGIO- AND STEREOSELECTIVITY
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Organocuprates induce 1,3- and direct substitution in 3-alkyl- and 3,3-dialkyl-1-bromo-1,2-dienes leading respectively to either terminal acetylenes or allenic hydrocarbons.The nature of the cuprate exerts a prominent role in determining both the regio- and the stereochemistry of these reactions.
- Caporusso, Anna Maria,Polizzi, Carmela,Lardicci, Luciano
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p. 6073 - 6076
(2007/10/02)
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