Diastereoselective Synthesis of Substituted 2-Phenyltetrahydropyrans as Useful Precursors of Aryl C-Glycosides via Selenoetherification
摘要:
The cyclization of several substituted 5-phenyl-pent-4-en-l-ols with selenium electrophiles along some mechanistic considerations is discussed. In particular, an efficient diastereoselective synthesis of a 2,3,5,6-tetrasubstitued tetrahydropyran is reported. These findings open an interesting approach: the use of chiral selenium electrophiles for cyclization of chiral substrates. The cyclized products are useful starting material for the synthesis of D- or L-aryl C-glycosides.
Diastereoselective Synthesis of Substituted 2-Phenyltetrahydropyrans as Useful Precursors of Aryl C-Glycosides via Selenoetherification
摘要:
The cyclization of several substituted 5-phenyl-pent-4-en-l-ols with selenium electrophiles along some mechanistic considerations is discussed. In particular, an efficient diastereoselective synthesis of a 2,3,5,6-tetrasubstitued tetrahydropyran is reported. These findings open an interesting approach: the use of chiral selenium electrophiles for cyclization of chiral substrates. The cyclized products are useful starting material for the synthesis of D- or L-aryl C-glycosides.
Bimetallic η<sup>6</sup>,η<sup>1</sup>SCS- and PCP-Pincer Ruthenium Palladium Complexes: Synthesis, Structure, and Catalytic Activity
作者:Sylvestre Bonnet、Martin Lutz、Anthony L. Spek、Gerard van Koten、Robertus J. M. Klein Gebbink
DOI:10.1021/om900984t
日期:2010.3.8
The synthesis of η6,η1 SCS- and PCP-pincer ruthenium palladium complexes [3]+−[6]+ by direct η6-coordination of [Ru(C5R5)]+ (R = H or Me) to the arene ring of η1-palladated ECE-pincer ligands (E = S or P) is described. In the resulting hetero bis-organometallic complexes, the π- and σ-electrons of the ECE-pincer phenyl anion are involved in η6- and η1-coordination to ruthenium(II) and palladium(II)
The cross-couplingreaction of allylic carbonates with organosilanes was found to proceed without fluoride ion activation under mild conditions by using a coordinatively unsaturated palladium complex as a catalyst. The reaction was assumed to proceed through an allylpalladium alkoxide derived from the allylic carbonate substrate and a palladium(0) species, the alkoxo ligand activating the organosilicon
Ni-Catalyzed Cross-Electrophile Coupling for the Synthesis of Skipped Polyenes
作者:Catherine P. McGeough、Alexandra E. Strom、Timothy F. Jamison
DOI:10.1021/acs.orglett.9b01019
日期:2019.5.17
Skipped polyenes featuring high ( E)-selectivity and varying methyl substitution patterns are synthesized using a nickel-catalyzed cross-coupling reaction between allyl trifluoroacetates and vinyl bromides. The utility of this cross-electrophile coupling is showcased in part by the synthesis of the RST fragment of the marine ladder polyether, maitotoxin. Construction of this fragment is particularly
Palladium catalyzed coupling of organostannanes with vinyl epoxides
作者:David R. Tueting、Antonio M. Echavarren、J.K. Stille
DOI:10.1016/0040-4020(89)80010-9
日期:1989.1
The coupling reaction of organotin reagents with vinyl epoxides, catalyzed by palladium, takes place at ambient temperatures, regioselectively, giving predominately the 1,4-addition product. Both aryl- and vinylstannanes undergo coupling in high yields, while acetylenic, allylic and benzylic tin reagents either give low yields or fail to couple. Although the double bond geometry in the vinylstannane
Palladium-catalyzed cross-coupling reaction of allyl carbonates with organostannanes
作者:Ana M. Castaño、Antonio M. Echavarren
DOI:10.1016/0040-4039(96)01406-2
日期:1996.9
Allylcarbonates are excellent substrates for the palladium(0)-catalyzed coupling reaction with stannanes under very mild conditions. The reaction proceeds via (η3-allyl)palladium complexes which undergo syn-anti equilibration with a rate similar to that of the transmetallation step.