73639-28-8Relevant academic research and scientific papers
A novel, short and repeatable two-carbon ring expansion reaction by thermo-isomerization: Easy synthesis of macrocyclic ketones
Nagel, Matthias,Hansen, Hans-Ju?rgen,Fra?ter, Georg
, p. 275 - 279 (2002)
A novel two-carbon ring enlargement procedure, in which medium- and large-ring 1-vinylcycloalkanols are thermoisomerized in a flow reactor system at temperatures of 600°C to about 650°C, produces the isomeric ring-expanded cycloalkanones directly and efficiently. This two-step ring expansion protocol can easily be applied several times successively. For e.g., the musk odorant cyclopentadecanone (Exaltone?) is prepared from cycloundecanone in two repetitive cycles. Thermo-isomerization of the corresponding ethynylic cycloalkanols gives in moderate yields the bishomologous α,β-unsaturated macrocyclic (E)-2-cycloalkenones. A reaction mechanism via alkyl hydroxyallyl biradical intermediates is proposed.
