106 Synthetic Routes to Nitrate Esters
Canfield and Rohrback^106 reported on the reaction of some electron-deficient difluo-
roaminoalkenes with dinitrogen pentoxide in chloroform at subambient temperatures. Contrary
to previous work that the β-nitro-nitrate ester should be the main product, the corre-
spondingvic-dinitrate esters were isolated from these reactions; 1,4-bis(N,N-difluoroamino)-
2,3-butanediol dinitrate (55), 3,4-bis(N,N-difluoroamino)-1,2-butanediol dinitrate (56) and
3-(N,N-difluoroamino)-1,2-propanediol dinitrate (57) were isolated in 30 %, 27 %, and 55 %
yields respectively, from the parent alkenes.
3.6.3 Metal salts
A suspension of thallium (III) nitrate in pentane at room temperature can react with alkenes
to givevic-dinitrate esters.^85 Cyclohexene reacts with this reagent to give 1,2-cyclohexanediol
dinitrate (85 %) (as a mixture of isomers) and 15 % cyclopentanecarboxaldehyde (hydride shift
in the dethallation step). Some alkenes react extremely slowly with this reagent e.g. isomeric
5-decenes.
3.6.4 Halonitroxylation
A number of reagents have been reported to add across the unsaturated bonds of alkenes to give
β-haloalkyl nitrates, a process known as halonitroxylation. The reaction of alkenes with a mix-
ture of iodine and dinitrogen tetroxide in chloroform can give high yields of the corresponding
β-iodoalkyl nitrate ester.^107 The same reaction with bromine yieldsβ-bromoalkyl nitrate esters,
although thevic-dibromoalkane is a major by-product.^107 Iodonium nitrate, a reagent prepared
from the reaction of silver nitrate with iodine monochloride in chloroform/pyridine, can add to
the double bond of an alkene to give any of three products, including:β-iodoalkyl nitrate esters,
β-iodoalkyl pyridinium nitrates, or alkenyl pyridinium nitrates depending on the substrate.^108
Bromonium nitrate, a reagent prepared from the reaction of bromine with silver nitrate in
chloroform/pyridine, reacts with alkenes to formβ-bromoalkyl nitrate esters orβ-bromoalkyl
pyridinium nitrates depending on the substrate and conditions.^109 Other reagents used for the
synthesis ofβ-haloalkyl nitrate esters include: mercury (II) nitrate and iodine,^110 mercury (II)
nitrate and bromine,^110 ,^111 and alkali metal nitrates and bromine water^112. The reaction of an
alkene with mercury (II) nitrate and a halogen is a process known as nitratomercuriation and
also yieldsβ-haloalkyl nitrate esters.^110 ,^111
3.7 Deamination
Barton and Narang^113 have prepared nitrate esters by treating primary and secondary alky-
lamines with dinitrogen tetroxide in the presence of an amidine base like DBU. Wudl and
Lee^114 conducted deamination reactions without any amidine base and reported much lower
yields of nitrate ester product. The use of an amidine base is not necessary if the amine substrate
is firstN-protected as its TMS derivative and then treated with dinitrogen tetroxide.^115 The
reaction of primary amines and nitramines with a solution of dinitrogen pentoxide in carbon
tetrachloride at− 30 ◦C is reported to lead to nitrate esters through deamination.^116