Radical Alkylphosphanylation of Olefins with Stannylated or Silylated Phosphanes and Alkyl Iodides
作者:Marie-Céline Lamas、Armido Studer
DOI:10.1021/ol200483p
日期:2011.5.6
Intermolecularconjugateradicaladdition reactions of secondary and tertiary alkyl radicals derived from the corresponding alkyl iodides to activated olefins such as α,β-unsaturated esters, amides, imides, nitriles, and sulfones are described. The adduct radicals are trapped by either diphenyl(trimethylstannyl)phosphane or the commercially available diphenyl(trimethylsilyl)phosphane as chain transfer
Me 3 P-catalyzed addition of hydrogen phosphoryl compounds P(O)H to electron-deficient alkenes: 1 to 1 vs 1 to 2 adducts
作者:Tian-Zeng Huang、Tieqiao Chen、Yuta Saga、Li-Biao Han
DOI:10.1016/j.tet.2017.10.070
日期:2017.12
Trimethyl phosphine was used as an efficient catalyst for the addition of P(O)-H compounds to electron-deficient alkenes. The addition reactions were generally conducted using a catalytic amount of Me3P under mild reaction conditions. Both 1 to 1 and 1 to 2 adducts were obtained.
A straightforward and practical strategy for hydrophosphorylation of electron-deficient alkenes and alkynes to access γ-ketophosphine oxides, enabled by CPE strategy in the absence of a metal, base, and redox reagent, has been described.
N-heterocyclic carbene catalyzed Michael additions have been revisited with 1,3-dialkyl- or 1,3-diarylimidazol(in)ium-2-carboxylates, that is, NHC center dot CO2 adducts, as the source of the free NHC catalysts in solution. Using these precatalysts, a number of efficient carba-, sulfa-, and phospha-Michael additions were achieved very conveniently, without the need for an external strong base to generate the NHC by deprotonation of an azolium salt. To further expand the scope of the procedure, some NHC-catalyzed sulfa-Michael/aldol organocascades were also investigated.
Asymmetric synthesis of trans-disubstituted cyclopropanes using phosphine oxides and phosphine boranes
作者:Celia Clarke、Stéphanie Foussat、David J. Fox、Daniel Sejer Pedersen、Stuart Warren
DOI:10.1039/b817433d
日期:——
The stereocontrolled synthesis of trans-disubstituted cyclopropylketones has been achieved from β-alkyl, γ-benzoyl phosphine oxides via a three-step cascade reaction incorporating an acyl transfer, phosphinoyl transfer and cyclisation to form the cyclopropane. Using Evans’ chiral oxazolidinone auxiliary and by masking the phosphine oxide moiety as a phosphine borane we have extended the method to the