G. Bucher, A laser flash photolysis study on 2-azido-N,N-diethylbenzylamine - The reactivity of iminoquinone methides in solution, EUR J ORG C, (13), 2001, pp. 2463-2475
Photolysis of 2-azido-N,N-diethylbenzylamine (1) in acetonitrile solution i
n the presence of various quenchers yields products of common nitrene chemi
stry (that is, derived from a didehydroazepine or a triplet nitrene), toget
her with products arising from trapping of stereoisomeric iminoquinone meth
ides, These intermediates are formed in a monophotonic process, by dediazot
ation of the precursor combined with a 1,4-hydrogen shift. The reactivity o
f the iminoquinone methides (IQM) towards a variety of quenchers, including
dienophiles and various nucleophiles, has been explored, using acetonitril
e, DMF and n-hexane as solvents. IQM reacts efficiently with electron defic
ient dienophiles [k(q)(maleic anhydride) = 2.4(.)10(7) M-1 s(-1), but not w
ith simple olefins such as cyclohexene. IQM shows low to medium reactivity
towards simple primary or secondary amines [k(q)(n-propylamine) = 6.4(.)10(
4) M-1 s(-1), medium reactivity with sterically unhindered simple alcohols
[k(q)(methanol) = 4.6(.)10(6) M-1 s(-1)], and high to very high reactivity
towards thiols [k(q)(n-dodecanethiol) = 1.1(.)10(9) M-1 s(-1)], diols, and
triols [k(q)(glycerol) = 1.5(.)10(8) M-1 s(-1)], and sugars [k(q)(D-glucose
) = 1.0(.)10(9) M-1 s(-1)]. IQM also reacts rapidly with cytosine: k(q)(cyt
osine) = 3.4(.)10(8) M-1 s(-1), while the reaction with adenine or thymine
is less efficient [k(q)(adenine)= 6.4(.)10(7) M-1 s(-1), k(q)(thymine)= 7.7
(.)10(6) M-1 s(-1)].