Regio- and Stereoselective Homocoupling of γ-Arylated tert-Propargyl Alcohols with Liberation of a Ketone Molecule and Successive Cyclization To Produce Fluorescent Dihydrofuran Derivatives
摘要:
1,1-Disubstituted 3-aryl-2-propyn-1-ols undergo unprecedented regio- and stereoselective homocoupling with liberation of a ketone molecule in the presence of a rhodium catalyst to give the corresponding 2-hydroxymethyl-(E)-enynes. The subsequent cyclization of the enynes in the presence of a base affords fluorescent 2,3-dihydrofuran derivatives.
Synthesis of Tetraarylallenes via Palladium-Catalyzed Addition-Elimination Reactions of 1,1,3-Triaryl-2-propyn-1-ols with Aryl Iodides
作者:Ming-Jung Wu、Li-Mei Wei、Li-Lan Wei、Wen-Bin Pan
DOI:10.1055/s-2005-872228
日期:——
The palladium-catalyzed reactions of tert-propargylic alcohols with aryl iodides afforded tetraarylallenes in good yields. This reaction involves: (1) oxidative addition of the aryl iodide to Pd(0); (2) arylpalladium intermediate coordination to the carbon-carbon triple bond of the 1,1,3-triaryl-2-propyn-1-ol and subsequent regioselective insertion of the alkynol to form β-hydroxyvinylpalladium species; and (3) β-elimination to produce the tetraarylallenes. Generally, the best results are obtained by employing 5 mol% of Pd(TFA)2, 10 mol% of PPh3, two equivalents of aryl iodide and five equivalents of Et3N in MeCN.
A new method for the efficient synthesis of hexahydro-1H-fluorene and octahydrobenzo[a]azulene derivatives through a ring-expansion strategy is reported. With an appropriate combination of thulium(III) trifluoromethanesulfonate and 13X molecular sieves, a range of unsaturated polycycliccompounds were obtained in good yields. Mechanism studies reveal that the reaction is more likely to undergo Meyer–Schuster
HFIP-Catalyzed Difluoroalkylation of Propargylic Alcohols to Access Tetrasubstituted Difluoroalkyl Allenes
作者:Jinshan Li、Wenxue Xi、Saimei Liu、Chenxi Ruan、Xiaochun Zheng、Jianguo Yang、Lei Wang、Zhiming Wang
DOI:10.1021/acs.orglett.1c02659
日期:2021.9.17
access structurally diverse tetrasubstituted difluoroalkyl allenes has been developed. This convenient procedure enables the rapid construction of highly functionalized multisubstituted fluorinated allenes in a mild and straightforward way. Furthermore, the synthetic potential of this methodology has been demonstrated by the facile synthesis of various structurally interesting fluorine-containing molecules
Iodo(III)-Meyer–Schuster Rearrangement of Propargylic Alcohols Promoted by Benziodoxole Triflate
作者:Roshayed Ali Laskar、Wei Ding、Naohiko Yoshikai
DOI:10.1021/acs.orglett.1c00039
日期:2021.2.5
rearrangement of propargylicalcohols into α,β-unsaturated ketones bearing an α-λ3-iodanyl group. This iodo(III)-Meyer–Schuster rearrangement proceeds under mild conditions and tolerates a variety of functionalized propargylicalcohols, thus complementing previously reported halogen-intercepted Meyer–Schuster rearrangement. The α-λ3-iodanylenones can be utilized for facile Pd-catalyzed cross-coupling for the
limiting oxidation can be a powerful tool for clarifying the role of oxidation in the transportproperties of crystalline rubrene, which is still unclear. Here, the synthesis of a series of substituted rubrene derivatives from dimerisation of propargyl alcohols is described together with the analysis of their stability to oxidation and electrochemical properties in solution. Millimetre-sized single crystals