Trityl-oxazolidinone

To create the free secondary amine group (N-H) fulleropyrrolidine, an amine-protected starting material can be used in the reaction (Cai et al., 2006). For instance, a trityl-oxazolidinone (using either triphenylmethyl- or better, 4-methoxytriphenylmethyl-protecting groups) can be reacted with C60 to yield the trityl-protected pyrrolidine (Figure 15.5). 

Figure 15.5 A trityl-protected pyrrolidine derivative of Cgg can be prepared by the reaction of N-trityl-oxazolidinone with a fullerene. Deprotection of the trityl group using methanesulfonic acid gives the secondary amine, which can be used in further conjugation reactions.

Another method for producing a chiral 3-carbon fragment, this time directly as a protected 5-hydroxymethyl-3-oxazolidin-2-one, is illustrated in scheme 9 (77). In this case, the amide 20 is converted to the 4-trityl ether 24. This undergoes very facile Hofmann rearrangement to give the 5-trityloxymethyl-3-oxazolidin-2-one 26 via the intermediate isocyanate 25. The oxazolidinone 26 is a protected version of 3-amino-1,2-dihydroxypropane. 

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