Oxocene oxidation

Cyclization of hydroxy dithioketals. Nicolaou et al.1 have used this reaction for construction of oxocenes. The most satisfactory method involves activation of the sulfur of the starting material (1) with AgC104 to produce an oxocene derivative (2), followed by C-S cleavage. This second step can be effected with (C6H5)3SnH (AIBN) or by oxidation to the corresponding sulfoxide or sulfone, which then is cleaved with... 

A route into the tra j-fused oxocene-oxane-oxepan ring systems involves oxidation of the macrocycle (99) with periodate, followed by cyclization with BF3 EtjO to give (100) in 63% yield (Equation (21)) <92TL3389>. 

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