Curran synthesis

For an excellent literature review of free-radical synthetic methods see D. P. Curran, Synthesis, 1988, pp. 417 and 489. 

Scheme 16.17 Regioselective Curran synthesis of 9- and 11-substituted camptothedns.

Dissolve it in Et20, add quinol (5(K)mg for 300mL, to stabilize it), dry over Na2S04, filter, evaporate and distil it under dry N2. It is a clear liquid if dry and decomposes very slowly. In the presence of H2O, traces of tributyl tin hydroxide are formed in a few days. Store it in sealed glass ampoules in small aliquots. It is estimated by reaction with aqueous NaOH when H2 is liberated. CARE stored samples may be under pressure due to liberated H2. [Van Der Kerk et al. J Appl Chem 7 366 1937, Ono et al. Tetrahedron 41 4013 1985, Neuman Synthesis 665 1987, Curran Synthesis 417 1988, Beilstein 4IV 4312.]... 

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