HINDERED ORGANOBORON GROUPS IN ORGANIC SYNTHESIS. 13. THE DIRECT PRODUCTION OF KETONES FROM ALIPHATIC ALDEHYDES BY A UNIQUE VARIANT OF THE BORON-WITTIG REACTION
In the presence of trifluoroacetic anhydride or N-chlorosuccinimide, aliphatic aldehydes react with dimesitylboron stabilised carbanions to give after work up, the corresponding ketones, a process wich is unique among Wittig type reactions.Yields of ketones are satisfactory in all cases except those involving the anion derived from the parent compound dimesitylmethylborane, wich give the corresponding alkenes.
Pelter, Andrew,Smith, Keith,Elgendy, Said,Rowlands, Martin
HINDERED ORGANOBORON GROUPS IN ORGANIC SYNTHESIS. 14. STEREOSELECTIVE SYNTHESIS OF ALKENES BY THE BORON-WITTIG REACTION USING ALIPHATIC ALDEHYDES
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.
Pelter, Andrew,Smith, Keith,Elgendy, Said,Rowlands, Martin
TRANSITION METHAL-CATALYZED SUBSTITUTION REACTION OF ALLYLIC PHOSPHATES WITH GRIGNARD REAGENTS
SN2-selective Grignard coupling with primary allylic diphenylphosphates was successfully achieved using Ni or Fe catalyst.In sharp contrast, a catalytic amount of CuCN*2LiCl promoted a SN2'-selective coupling reaction.In the presence of the copper catalyst, stereochemically homogeneous γ-disubstituted allyl Grignard reagents reacted at the less substituted allylic terminus (α-position) with an allylic diphenylphosphate selectively without losing the double bond geometry.
Hindered organoboron groups in organic chemistry. 25. The condensation of aliphatic aldehydes with dimesitylboryl stabilised carbanions to give alkenes
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.
Pelter,Smith,Elgendy
p. 7119 - 7132
(2007/10/02)
DECARBOXYLATION OF ALIPHATIC α,β-UNSATURATED ALDEHYDES USING THE WILKINSON COMPLEX
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Grigor'eva, N. Ya.,Pinsker, O. A.,Semenovskii, A. V.
p. 593 - 594
(2007/10/02)
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