109930-25-8Relevant articles and documents
Diastereo- And enantioselective ruthenium-catalyzed C-C coupling of 1-arylpropynes and alcohols: Alkynes as chiral allylmetal precursors in carbonyl anti-(α-Aryl)allylation
Xiang, Ming,Ghosh, Ankan,Krische, Michael J.
supporting information, p. 2838 - 2845 (2021/03/01)
Highly tractable 1-aryl-1-propynes, which are readily accessible via Sonogashira coupling, serve as chiral allylmetal pronucleophiles in ruthenium-JOSIPHOS-catalyzed anti-diastereo- and enantioselective aldehyde (α-aryl)allylations with primary aliphatic or benzylic alcohol proelectrophiles. This method enables convergent construction of homoallylic sec-phenethyl alcohols bearing tertiary benzylic stereocenters. Both steric and electronic features of aryl sulfonic acid additives were shown to contribute to the efficiency with which a more selective and productive iodide-bound ruthenium catalyst is formed. As corroborated by isotopic labeling studies, a dual catalytic process is operative in which alkyne-to-allene isomerization is followed by allene-carbonyl reductive coupling via hydrogen auto-transfer. Crossover of ruthenium hydrides emanating from these two discrete catalytic events is observed. The utility of this method is illustrated by conversion of selected reaction products to the corresponding phenethylamines and the first total syntheses of the neolignan natural products (-)-crataegusanoids A-D.
Study of the pyrolytic chemistry of isobenzofurylmethyl benzoates
Chen, Ping-Shu,Chou, Chin-Hsing
, p. 17115 - 17126 (2007/10/03)
Pyrolysis of (1-isobenzofuryl)methyl benzoate (9a), produced in situ from flash vacuum pyrolysis of (7-oxa-1-benzonorbornenyl)methyl benzoate (10a), gave methylenebenzocyclobutenone (4), 2-ethynylbenzaldehyde (5) and benzocyclopentadienone (6). The deuterium-labeled study indicated that the mechanism for the formation of these products involved the double migrations of benzoate group in 9a. Pyrolysis of (3-methyl-1-isobenzofuryl)methyl benzoate (9c) gave 1,3-dimethylene-1,3-dihydroisobenzofuran (33), which is stable in benzene and hydrolyzed rapidly in chloroform to give 1,2-diacetylbenzene (35).
Substituent Effects in the Aliphatic Claisen Rearrangements of Substituted (1-Methyl-3-oxahexa-1,5-dienyl)amines: Synthesis of Substituted 2-Aminopent-4-enals. Alternative -Sigmatropic Shifts in Related Aromatic Systems.
Barluenga, Jose,Aznar, Fernando,Liz, Ramon,Bayod, Miguel
, p. 5190 - 5194 (2007/10/02)
The series of substituted β-allyloxy enamines 4 was allowed to undergo Claisen rearrangement.The reaction proved to be faster for enamines derived from aliphatic than those from aromatic amines, the general substituent effects fitting Gajewski's oxaallyl-allyl radical model for these processes.The high stereoselectivity observed in these reactions leading to the 2-aminopent-4-enals 5 was assumed to occur via the more stable chairlike transition state.A different -sigmatropic course, leading to the 2-amino-2-methylpropanals 20, was observed when the allylic double bond is part of an aromatic system.