85336-75-0

Upstream product

• 5783-23-3 (E)-1-phenyl-1-(p-methoxyphenyl)-2-bromoethylene 
• 85336-52-3 (RR,SS)-2-phenyl-2-((p-methoxyphenyl)ethyl-1-d)trimethylammonium bromide 

Downstream Products

• 85336-52-3 (RR,SS)-2-phenyl-2-((p-methoxyphenyl)ethyl-1-d)trimethylammonium bromide 

Relevant academic research and scientific papers

Mechanisms of Elimination Reactions. 39. Steric and Electronic Effects on Stereochemistry in Eliminations from Primary Alkyltrimethylammonium Salts

Percentages of syn elimination have been determined by high-field NMR on the products of elimination from R1R2CHCHDX.The results for X=OTs with t-BuO(-)/t-BuOH at 60 deg C were the following (R1, R2, percent syn): p-MeOC6H4, C6H5, 3.7; p-ClC6H4, C6H5, 29; p-ClC6H4, C6H5, 0 in EtO(-)/EtOH.For X=NMe3(+) with OH(-) in 50 molpercent Me2SO-50 molpercentH2O at 60 deg C, the results were as follows (R1, R2, percent syn): p-MeOC6H4, C6H5, 60; p-ClC6H4, C6H5, 72.For Ar(i-Pr)CHCHDNMe3(+) with OH(-) in 50 molpercent Me2SO-50 molpercent H2O at 80 deg C, the results were as follows (Ar, percent syn): m-ClC6H4, 78.6; p-ClC6H4, 69.5; C6H5, 59.6; p-EtC6H4, 58.3; p-t-BuC6H4, 60.5.Overall rates in this series were dissected into syn and anti rates, which fitted the Hammett equation to give ρsyn=3.69 +/- 0.20 and ρanti=3.02 +/- 0.22.This result supports the conclusion that syn elimination has a more carbanionic transition state than anti.The lower percent syn with X=OTs than with X=NMe3(+) is ascribed to the lesser steric requirements of OTs.

Mechanisms of Elimination Reactions. 36. Stereochemistry and Transition-State Structure in Eliminations from Primary Alkyltrimethylammonium Salts

A study of stereochemistry of elimination in E2 reactions of R1R2CHCHDNMe3+ reveals that syn elimination can become the major reaction path when R1 and R2 are both bulky groups such as aryl or branched alkyl.With OH-/50percent Me2SO-H2O at 80 deg C, the percent of syn is 68.5 for R1 = Ph, R2 = i-Pr; 61.9 for R1 = Ph, R2 = p-MeOPh ; 26,5 for R1 = Ph, R2 = CH3.With n-BuO-/50percent Me2SO-n-BuOH, the percent of syn runs 61.5 for R1 = Ph, R2 = i-Pr; 12 for R1 = n-Bu, R2 = Me; and 1 = n-Bu, R2 = D.The results can be rationalized by a simple conformational argument in which steric interactions between bulky β-substituents and the leaving trimethylammonio group destabilize the trasition state for anti elimination.Primary β-tritium, secondary α-tritium, and primary α-14C isotope effects were determined on the (2,2-diphenylethyl)trimethylammonium ion and compared with similar data on the (2-phenylethyl)trimethylammonium ion, which eliminates by an exclusively anti mechanism.The extent of proton transfer in the transition state seems not to differ widely between the two systems, but the extent of C-N cleavage appears less in the 2,2-diphenylethyl system.Hammett ρ values are smaller in the 2,2-diphenylethyl system, though their interpretation presents ambiguities.