basis of a study of the O-phenylation of 3-phenyl-2-propyn-1-ol with diphenyliodonium triflate and t-BuONa, a variety of 4-aryl-3-iodo-2H-benzopyrans were prepared in good to moderate yields in one pot from the reaction of 3-aryl-2-propyn-1-ols with diaryliodonium triflates and t-BuONa, followed by the treatment with N-iodosuccinimide and BF3·OEt2, under transition-metal-free and mild conditions. The formed
Broadly Applicable Ion Pair-Assisted Nucleophilic Substitution of sp<sup>3</sup>-Carbon Electrophiles with Alkynyltrifluoroborates
作者:Shiwen Liu、Cláudio F. Tormena、Gerald B. Hammond、Bo Xu
DOI:10.1021/acs.orglett.2c02507
日期:2022.9.2
smoothly with a wide range of sp3-carbon electrophiles, including propargyl methanesulfonates and unactivated alkyl triflates, to give Sonogashira-type products, via a novel ion pair-assisted nucleophilicsubstitution mechanism. An ion pair–organic complex, investigated using computational chemistry and in situ NMR experiments, may play a crucial role in this reaction.
Asymmetric syntheses of diarylheptanoid natural products (−)-centrolobine and (−)-de-O-methylcentrolobine via hetero-Diels–Alder reaction catalyzed by dirhodium(II) tetrakis[(R)-3-(benzene-fused-phthalimido)-2-piperidinonate]
Catalytic asymmetric syntheses of (-)-centrolobine and (-)-de-O-methylcentrolobine have been achieved, incorporating a hetero-Diels-Alder (HDA) reaction between 4-aryl-2-silyloxy-1,3-butadienes and phenylpropargyl aldehyde derivatives as a key step. The HDA reaction using dirhodium(II) tetrakis[(R)-3-(benzene-fused-phthalimido)-2-piperidinonate], Rh-2(R-BPTPI)(4), as a chiral Lewis acid catalyst provides exclusively cis-2,6-disubstituted tetrahydropyran-4-ones in up to 93% ee. (C) 2007 Elsevier Ltd. All rights reserved.
Regiocontrolled Annulation of Benzocyclobutenols with Alkynes
作者:Qin-Qiong Zeng、Yong-Qi Wang、Lang Cheng、Bi-Qin Wang、Ping Hu、Feijie Song
DOI:10.1021/acs.orglett.2c01023
日期:2022.4.29
2H-furan-, pyran-, and oxepine-fused naphthalenes. Furthermore, the 2H-furan motif may undergo a ring-opening reaction through Fe-catalyzed reductive C–O bond cleavage. As a consequence, the formal intermolecular annulation of 2-hydroxybenzocyclobutenols with alkynes was realized with complete regioselectivity through a two-step protocol.