Delta-ethylenic carbonyl cpd. prepn. using oxy-Cope transposition - from a di:ethylenic alcohol, using stoichiometric mercuric salt or stoichiometric lithium salt and catalytic mercuric salt

摘要

Process for the preparation of delta-ethylenic carbonyl cpds. (I) by transposition of diethylenic alcohols (II), at -40 to 80 deg.C (pref. -5 to 30 deg.C) in the presence of a practically stoichiometric quantity of a mercuric salt or of a catalytic quantity of mercuric salt and a stoichiometric quantity of a lithium sa followed by isolation of the product, opt. after treatment of the reaction medium with a reducing agent in basic medium (where R1, R2, R4, R5, R6 indendently are H or a 1-20 acylic radical whose chain may contain one or more double or triple bonds; R3 is 1-20C acyclic whose chain may contain one or more double or triple bonds or R1 and R3 together are trimethylene or R3 and R4 together are -(CH2)n- (opt. substd. by 1-4C alkyl groups) and n is 3-20). (I) are intermediates for biologically active cpds. e.g. vitamins A and E, agricultural chemicals and perfumes. The present invention allows the oxy-Cope or Cope enologenic transposition to be effected under conditions which are practical for industrial use.