An example of the amine catalyzed retro-aldol reaction. Dehydration and cleavage of 1-(3-chlorophenyl)-1-methyl-2-phenyl-2-(2-pyridine)ethanol. A case of kinetic and thermodynamic competition

Dissecting Alkynes: Full Cleavage of Polarized C≡C Moiety via Sequential Bis-Michael Addition/Retro-Mannich Cascade

“…(a) Two patterns for H-bond assisted retro-aldol fragmentation: O–H···N assistance identified by Hansen et al and N–H···O assistance reported in this work. (b) Stereoelectronic alignment of the second amine lone pair with the breaking C–C bond in the transition state of Ph- and Me-substituted substrates.…”

“…The first amine provides an N–H moiety for proton transfer to the developing negative charge at the enolate oxygen. The effect of N–H···O is interesting considering that its formal reverse, an O–H···N interaction, has been suggested to play an important role in amine-catalyzed retro-aldol reactions . The second amine provides direct stereoelectronic assistance to the C–C bond cleavage via a hyperconjugative n N → σ* C–C interaction.…”

Dehydrative metabolites of 1-(3-chlorophenyl)-1-methyl-2-phenyl-2-(2-pyridine)ethanol as potential hypocholesteremic agents

“…It has been reported that the 2-(4-hydroxyphenyl) derivative 3a is a pharmacologically active metabolite of la2 in rats, and previous chemical studies indicated that dehydration of la yielded the unsaturated isomers 2a and 2b. 3 Therefore, it was postulated that isomers 2a and 2b and their hydroxylated derivatives 4a and 4b could be metabolites of la and might be involved in the species-specific activity of la. lb, R = H 3b, R = OH Cl 2a, R = H 2b, R = H 4a, R = OH 4b, R = OH This paper reports the synthesis of compounds 2a,b, 4a,b, 5, and 8 together with the determination of their hypocholesteremic and estrogenetic activities.…”