Reduktive Fragmentierung mit Natriumborhydrid^1,2)

Abstract

Die reduktive Fragmentierung von 1‐Methyl‐4‐tosyloxy‐bicyclo[2.2.2]octanon‐(2) (1) und seines Äthylenacetals (6) mit Natriumborhydrid führt zu 1‐Methyl‐1‐formyl‐4‐methylencyclohexan (3) bzw. dessen Äthylenacetal (8).

Nucleophilic eliminative ring fission

“…An interesting comparison is seen in the adamantyl system:366 •367 The reaction is 15 times faster for X = O366 than for X = S,367 (an exo:S=C:C:6 process), the difference being ascribed to the more favorable formation of a carbonyl than a thiocarbonyl group. Alignment of the ruptured bonds is perfect in these instances as in the fission of the ketone 126 following addition to the carbonyl group: 368 Me Me OTs 126…”