and (B) stoichiometric amounts of the reactants and a catalytic amount of Nafion®-TMS were heated to 90–100 °C in the absence of solvent. The following ketones have been tested: 2-bromo-1-phenyl-1-ethanone, 2-bromo-cyclopentenone, 3-bromo-3-methyl-2-butanone, 3-chloro-3-methyl-2-butanone, 1-bromo-3,3-dimethyl-2-butanone, 1-chloro-3,3-dimethyl-2-butanone, 2-bromocyclohexanone, 2-chloro-1-cyclohexyl-1-ethanone
Five- and six–membered cyclic α-acylvinyl anionic synthons: synthesis of α-trimethylsilyl-α,β-unsaturated cycloalkenones and their conversion into 2-(hydroxydimethylsilyl)cycloalk-2-enones through carbon–silicon bond scission
作者:Divya Jyothi、HariPrasad Suresh
DOI:10.3998/ark.5550190.0013.618
日期:——
Five- and six-membered I±-trimethylsilyl-I±,I²-unsaturated cycloalkenones were prepared by the Wurtz-Fittig coupling reaction of the corresponding 6-bromo-1,4-dioxaspiro4,ncycloalk-6-enes with sodium and chlorotrimethylsilane. Upon treatment with anhydrous AlCl3, the compounds underwent carbon-siliconbondscission to yield a novel class of compounds: the 2-(hydroxydimethylsilyl)cycloalk-2-enones.
Palladium-catalyzed cyclotrimerization was applied to three strainedcycloalkynes. Pd(PPh 3 ) 4 and Pt(PPh 3 ) 4 -catalyzed cyclotrimerizations of cyclohexyne (2) afforded dodecahydrotriphenylene (3) in 64% and 62% yields, respectively, but subjecting cyclopentyne to the same conditions failed to afford isolable amounts of the cyclotrimer. Finally, decacyclene (15), a putative C 6 0 -fullerene precursor
Enantioselective construction of the tricyclic core of curcusones A–D <i>via</i> a cross-electrophile coupling approach
作者:Austin C. Wright、Brian M. Stoltz
DOI:10.1039/c9sc04127c
日期:——
Herein we report our recent progress toward the enantioselective total synthesis of the diterpenoid natural products curcusones A–D by means of complementary Stetter annulation or ring-closing metathesis (RCM) disconnections. Using the latter approach, we have achieved the concise construction of the 5–7–6 carbocyclic core embedded in each member of the curcusone family. Essential to this route is
Small-Scale Procedure for Acid-Catalyzed Ketal Formation
作者:Austin C. Wright、Yun Emily Du、Brian M. Stoltz
DOI:10.1021/acs.joc.9b01541
日期:2019.9.6
A modified procedure for dehydrative ketal protections is disclosed, which serves as an alternative to the classic Dean–Stark protocol. Studies show that this new procedure can outperform the Dean–Stark apparatus on small scales and thus serves as a complementary approach to effect dehydrative ketalizations. A detailed procedure for this apparatus is presented.