(E)-Selective Synthesis of γ-Substituted-β-(Ethoxycarbonyl)Allylsilanes Utilising Ethyl 2-Diphenylphosphono-3-(Trimethylsilyl)Propionate. Improved Synthesis of 11 Membered Carbocycle by a Homo-Cope Reaction

Abstract

( E)-γ-Substituted-β-(ethoxycarbonyl)allylsilanes were selectively synthesised by Horner-Wadsworth-Emmons reaction utilising ethyl 2-diphenylphosphono-3-(trimethylsilyl)propionate.

Correlation of Hydrolysis and Desilylation of 2‐[(Trimethylsilyl)methyl]acrylate Derivatives in Aqueous Alkali Solutions

“…Ethyl (2E) [12] have already been reported. Typical Procedure of the Hydrolysis and Desilylation Reaction.…”

“…The procedure by which 4g (94% yield) was synthesized from 4-methoxybenzaldehyde has been reported in our previous paper [12].…”

“…Compounds 1c -e and 4c -e have an aliphatic R group, and the C¼C bond of the acrylate is not further conjugated, while compounds 1f -h and 4f -h bear an aromatic ring conjugated to the acrylate moiety. These compounds were synthesized from the corresponding aldehydes via a (Z)-selective [5a] and an (E)-selective [12] Horner-Wadsworth-Emmons (HWE) reaction, respectively (Scheme 2). Each of the substrates was obtained with good (Z)-or (E)-selectivity, except for 1c and 1e which were obtained with low (Z)-selectivity ((E)/(Z) 44 : 56 for 1c and 22 : 78 for 1e) when hexamethyldisilazane potassium salt (KHMDS)/ [18]crown-6 was used as the base, while the standard method with NaH as the base [5a] afforded the (E)-product as the major isomer.…”

Palladium-Catalyzed Regio- and Stereoselective Cross-Coupling of Baylis-Hillman Adducts and Bimetals: A Novel Method for the Synthesis of Substituted Allylsilanes and Allylgermanes

“…The stereochemistry of the allylmetals was determined to be Z using 1 H and 13 C NMR spectroscopy and by comparison with the literature. , Only trace quantities of the E isomers were detected. The Z selectivity is presumably a consequence of thermodynamic control.…”