Untersuchungen über Acetylene VI: Die Reaktion der Acetylene mit Persäuren. Acetylenoxyde

Abstract

Die Acetylene erweisen sich in einigen Fallen, z. B. gegenuber katalytisch erregtem Wasserstoff, als reaktionsfahiger als die entsprechenden Athylene. Denn es ist moglich, auch mit vergifteten Katalysatoren die ersteren zu hydrieren, denen gegeniiber die letzteren sich refraktar verhalten. Umgekehrt finden sich in der Literatur zahlreiche Beispiele dafiir, daB Halogene an Plefine wesentlich leichter angelagert werden als an Acetylene. So wird im All$-acetylen Brom zuniichst an die Doppelbi~dung addiertz) :Ein ahnlicher Unterschied besteht bei der Anlagerung von Sauerstoff mittels Persauren. Denn wahrend es durch P. Prileshajews) schon lange nachgewiesen ist, daB Olefine schon bei Oo ganz glatt und quantitativ Sauerstoff anlagern und Athylenoxyde bilden, haben J. Boeseken

Oxirenes

“…This compound, however, should certainly not be isolable under normal conditions, and the reaction of alkynes with strong oxidants is known to give other products. 23 The next claim of a successful oxirene synthesis8 involved a nonoxidative approach (IIID1), but in 1952 Shubach and Franzen9 claimed the oxidation of 5-decyne (9) to dibutyloxirene (10) with peroxyethanoic acid24 (Scheme II). However, Franzen soon showed that the product of the oxidation was in Scheme III fact 6-decen-5-one (11) (Scheme II), and went on to show that the oxidation of alkynes with peroxyethanoic acid can produce, besides a,/3-unsaturated ketones, products plausibly derivable from them (eq 3)25 or from ketenes (eq 4).…”

Specific Microdiffusion Method for the Determination of Fluorine Based on the Lanthanum-Alizarin Complexone Color System

“…Epoxidation of acetylenes to produce oxirenes initially is not only slower but was also found by Schlubach and Franzen (16) to result in cleavage of the triple bond to acids of shorter chain length. Because of this difference in reactivity, peroxyacetic acid may be employed for selective epoxidation of an olefin bond that is conjugated with a triple_bond.…”

Evidence for oxirene intermediates in the peroxidation of acetylenes

“…Oxirenes, potential 4tt antiaromatic systems,1 have been frequently proposed as transient intermediates in the peroxyacid oxidation of acetylenes. [2][3][4][5][6][7] The results of the earlier product2-6 and kinetic studies7 are consistent with but do not uniquely require the oxirene mechanism. Recent evidence seems to favor a pathway featuring ketocarbenes as reactive intermediates.8 We now present evidence which, for the first time, compellingly implicates oxirenes as the first-formed intermediates in the peroxidation of acetylenes.…”