- Simple Stereospecific Syntheses of (E)-1-Chloro(or Bromo)alk-1-enes from Alk-1-ynes via Hydroboration
-
Stereochemically pure (E)-1-chloro(or bromo)alk-1-enes were obtained in sufficiently good yields from alk-1-ynes via hydroboration with dialkylborane followed by reactions with facile reagents; corresponding copper(II) halides, in the presence of a small
- Masuda, Yuzuru,Hoshi, Masayuki,Arase, Akira
-
p. 2723 - 2726
(2007/10/02)
-
- Reactions of Alkylmercurials with Heteroatom-Centered Acceptor Radicals
-
The relative reactivities of alkylmercury halides toward PhS., PhSe., or I. decrease drastically from R = tert-butyl to R = sec-alkyl to R = n-butyl, indicative that R. is formed in the rate-determining step in the attack of these radicals upon RHgCl.The alkyl radicals thus formed will enter into chain reactions in which a heteroatom-centered radical (A.) is regenerated from substrates such as RS-SR, ArSe-SeAr, ArTe-TeAr, PhSe-SO2Ar, Cl-SO2Ph; ZCH=CHA (A = Cl, I, SPh, SO2Ph); or PhCCHA (A = I, SPh, SO2Ph). β-Styrenyl (PhCH=CHA, Ph2C=CHA) and β-phenethynyl (PhCCA) systems with A = I, Br, SO2Ph also enter into chain reactions with mercury(II) salts with the ligands PhS, PhSe, PhSO2, or (EtO)2PO.The relative reactivities of a series of reagents toward t-Bu. and of PhCH=CHA, Ph2C=CHA, and PhCCA toward c-C6H11. are reported as well as the regioselectivity of t-Bu. attack observed for 1,2-disubstituted ethylenes (ZCH=CHA) with Z and A from the group Ph, Cl, Br, I, SO2Ph, SPh, Bu3Sn.Reactions of (E)- and (Z)-PhCH=CHI or MeO2CCH=CHI with t-Bu. or c-C6H11. occurred in a regioselective and stereospecific (retention) manner.Reactions of (E)- and (Z)-ClCH=CHCl occurred in a nonstereospecific manner in which the E/Z product ratio increased with the bulk of the attacking radical.A similar effect on the E/Z product ratios was observed for (Z)-MeO2CCH=CHCl.
- Russell, Glen A.,Ngoviwatchai, Preecha,Tashtoush, Hasan I.,Pla-Dalmau, Anna,Khanna, Rajive K.
-
p. 3530 - 3538
(2007/10/02)
-
- SYNTHESIS OF(E) AND (Z) ALKENES VIA PALLADIUM OR NICKEL-CATALYZED REACTION OF VINYL CHLORIDES WITH GRIGNARD REAGENTS.
-
We herein described (i) a useful transformation of (E) and (Z) vinyl chlorides into E (and Z) olefins and (ii) an efficient preparation of monoenic alcohols or acetates and its application to insect pheromones.
- Ratovelomanana, Victorin,Linstrumelle, Gerard
-
p. 179 - 188
(2007/10/02)
-