127392-75-0Relevant academic research and scientific papers
Stereodivergent synthesis of alkenes by controllable syn-/anti-fragmentation of β-hydroxysulfonyl intermediates
Górski, Bartosz,Basiak, Dariusz,Grzesiński, ?ukasz,Barbasiewicz, Micha?
, p. 7660 - 7663 (2019/08/30)
The reduction of the carbonyl group in acylated trifluoroethyl alkanesulfonates follows the Felkin-Ahn selectivity, and the so-formed diastereomeric β-hydroxysulfonyl intermediates undergo syn- and anti-fragmentation, depending on the reaction conditions. In effect, isomeric E- and Z-alkenes are formed in a stereodivergent manner, which mimics the mechanistic manifold of the Peterson olefination.
Olefination with Sulfonyl Halides and Esters: E-Selective Synthesis of Alkenes from Semistabilized Carbanion Precursors
Górski, Bartosz,Basiak, Dariusz,Talko, Alicja,Basak, Tymoteusz,Mazurek, Tomasz,Barbasiewicz, Micha?
supporting information, p. 1774 - 1784 (2018/04/27)
Carbanions of sulfonyl halides and activated sulfonates add to carbonyl compounds, and so-formed aldol-type adducts spontaneously fragment into olefins. This transformation mimics the one-pot Julia olefination with (hetero)aryl sulfones, but the mechanism of fragmentation involves a four-membered intermediate, typical for reactivity of phosphorus reagents. Moreover, in contrast to the reactions of sulfones, sulfonates of fluorinated alcohols (TFE and HFI) produce byproducts that are easily removed during workup. In our report, we focus on reactions of unstabilized and semistabilized carbanion precursors: alkylsulfonates, and allyl- and benzylsulfonates, respectively. In particular for semistabilized systems, olefins were synthesized as predominant E isomers in good yields. The presented studies reveal that optimal reaction conditions, including the type of base and alcohol groups of the sulfonates, are different depending on stabilization of the carbanion precursors and structure of the carbonyl substrates. The practical synthetic guide is supplemented with a discussion of the mechanism, based on reactivity studies of intermediates and identification of side-products.
A New Horner-Wadsworth-Emmons type coupling reaction between nonstabilized β-hydroxy phosphonates and aldehydes or ketones
Reichwein, John F.,Pagenkopf, Brian L.
, p. 1821 - 1824 (2007/10/03)
Treatment of nonstabilized β-hydroxy phosphonic acid mono methyl esters with diisopropyl carbodiimide at ambient temperature leads to clean stereospecific elimination. The phosphonic acid mono alkyl esters are accessible by the selective partial saponification of dimethyl or diethyl alkyl phosphonates with NaOH or MgBr2. Isolated yields over both hydrolysis and elimination steps average 55-75%.
Hindered organoboron groups in organic chemistry. 25. The condensation of aliphatic aldehydes with dimesitylboryl stabilised carbanions to give alkenes
Pelter,Smith,Elgendy
, p. 7119 - 7132 (2007/10/02)
In the presence of protic acids the condensation of aliphatic aldehydes with dimesitylboryl stabilised carbanions results in alkenes. In the presence of strong acids such as HCl or CF3SO3H, the products contain > 90% of E-alkenes in all cases tried. When acetic acid is used, the Z-alkenes may result predominantly, particularly in the cases of R(S)CHO and R(t)CHO.
HINDERED ORGANOBORON GROUPS IN ORGANIC SYNTHESIS. 14. STEREOSELECTIVE SYNTHESIS OF ALKENES BY THE BORON-WITTIG REACTION USING ALIPHATIC ALDEHYDES
Pelter, Andrew,Smith, Keith,Elgendy, Said,Rowlands, Martin
, p. 5647 - 5650 (2007/10/02)
In the presence of HX, carbanions Mes2BCHLiR1 react with aliphatic aldehydes to give alkenes.The stereochemistry of product alkene depends upon the nature of HX.
