Hydrolyses of terpenoid diphosphates. Effects of azide ion on products of hydrolysis

Abstract

Hydrolysis of geranyl diphosphate (GPP) at pH 7 in water gives largely linalool (LOH) + geraniol (GOH) in the ratio of 3:1. Added N−3 generates mixed acylic allylic azides and increases the LOH GOH ratio to 15:1 in 2 M NaN3, but does not speed up the overall reaction. Hydrolysis of neryl diphosphate (NPP) gives largely α‐terpineol (TOH) +p LOH, but their ratio is not very sensitive to NaN3 concentration although acyclic azide and small amounts of α‐terpinyl azide (TN3) are formed. Hydrolysis of α‐terpinyl diphosphate (TPP) gives large amounts of the cyclic alkenes, limonene and terpinolene. Added N−3 does not change the amount of elimination, but increases the ratio of limonene to terpinolene, and diverts some substitution product to TN3. Trapping of carbocationic species from GPP by N−3 is sharply increased by addition of Mn2+, which also catalyzes the overall reaction. Products of reaction of GPP are derived from acyclic intermediates and of NPP from acyclic and cyclic intermediates,