2,2 ’2”-Trichloroethoxycarbonyl Troc , protecting group

Scheme 12, 2,5-Dimethylpyrrole and 2,2 2 trichloroethoxycarbonyl(Troc) protecting groups for enzymatic synthesis of lactosamine.

Due to the relatively high stability of the N-2,2,2-trichloroethoxycarbonyl (Troc) group to acids and its selective removal by zinc reduction even in the presence of Al-benzyloxy-carbonyl derivatives, it can offer interesting possibilities in the syntheses of particular pep-tidic compounds for example, it has been used for N -protection of lysine in the synthesis of The Af -Troc-protected lysine is readily prepared by reaction of the copper(II) complex with 2,2,2-trichloroethyl chloroformate (Troc-Cl)h d or by reaction of Z-Lys-OH (obtained via the benzylidene route, see Section 2.1.2.2.1.3) with 2,2,2-trichloroethyl chlor-oformate.f ... 

Cleavage of Troc groups The 2,2,2-trichloroethoxycarbonyl protecting group of. imines is removed in neutral conditions using 10% Cd-Pb in THF containing NH OAc (5 - amples, 89-94%). 

Scheme 19 Use of synthetic -participating or the natural N-acetylated donors for the synthesis of p-o-N-acetyl glucosamine motifs. LG = leaving group P = promoter PG = participating group Phth = Phthaloyl R = protecting group TCA = trichloroacetyl TFA = trifluoroacetyl Troc = trichloroethoxycarbonyl...

An excerpt of a synthesis of the potent antitumour agent FR-900482 [Scheme 3.126] illustrates the use of an N, O-acetal with additional Af-protection in the form of a 2,2,2-trichloroethoxycarbonyl (TVoc) group (see section 8.3.7) in a multifunctional environment.244 245 The A 0-acetal survived the mildly acidic conditions required to deprotect the p-methoxybenzyl group that preceded the formation of the triflate 1263. Later, reductive cleavage of the Troc group and simultaneous hydrolysis of the oxazolidine ring was accomplished in a single... 

---