Cbz group

BuMc2SiH, Pd(OAc)2, CH2CI2, Et3N, 100% yield. Cbz groups and Alloc groups are also cleaved, but benzyl ethers are stable. 

CF3CO2H, phenol, reflux, 30 min, 2-5% yield. In this case an 5-Cbz group is removed. 

CF3COOH, reflux, 30 min, quant. An A -Cbz group is also removed under these conditions. 

InHBr, AcOH, 25°, 30min. The5-Cbzgroup is removed slowly under these conditions, but the N-Cbz group is completely cleaved, thus providing some selectivity in the protection scheme for cysteine. 

Direct conversion of an Fmoc group to a Cbz group KF, TEA, DMF, A-benzyloxycarbonyloxy-5-norbomene-2,3-dicarboximide, 7-12 h, 83-99% yield. ... 

Sm, I2, MeOH, reflux 24 h, 95% yield. This reagent also cleaves the Cbz group and other carbamates and esters. 

In addition to standard catalytic hydrogenolysis, methods for transfer hydrogenolysis using hydrogen donors such as ammonium formate or formic acid with Pd-C catalyst are available.216 The Cbz group also can be removed by a combination of a Lewis acid and a nucleophile for example, boron trifluoride in conjunction with dimethyl sulfide or ethyl sulfide.217... 

Due to some stability concerns with the N-Cbz group of 8 at high temperatures, compound 25 was used as a model substrate for the reaction. Substrate 25 was irradiated for 2 min (internal temperature reached 185 °C) in a variety of solvents and all thermal reactions reached >95% conversion (Table 6.1). Both aprotic polar solvents (entries 6 and 9) and protic polar solvent (entry 7) gave poor assay yields of product 26. With nonpolar solvents (entry 10) such as o-xylene and xylenes, the rearrangement reaction provided the highest assay yield and proved to be the best solvent choice [9e],... 

Figure 1 Removal of carbobenzyloxy (Cbz) groups from protected amino acids.

The benzyl—nitrogen bond is not so easily cleaved as the benzyl—oxygen bond, unless the O-benzyl group is sterically hindered. This difference in activity allows the selective removal of the O-benzyl function in a molecule containing both N-benzyl and O-benzyl protecting groups. The selectivity can be reversed if the amine is protected by the Cbz group. If a small amount of amine (e g., butylamine) is added, then the selective removal of N-benzyl amines can be achieved.292... 

Alternatively, 138 can be converted to CBZ carbamate 142 using standard conditions (Scheme 4.30). This 5-bromoisoindoline was transformed to stannane 143 in one step with bistributyltin in the presence of a palladium catalyst. The stannane was treated with 136 under Stille conditions to afford coupled product 144. The resulting ester was hydrolyzed with sodium hydroxide, and the CBZ group was removed under hydrogenolysis conditions to deliver garenoxacin (4) (Hayashi et al., 2002). 

Levomepro- mazine MS-M No significant difference between groups CBZ group needed less levomepromazine... 

The cascade hydroformylation-allylboration-hydroformylation of ( )-aminoallylborate 85 catalyzed by Rh(acac)(CO)2-BIPHEPHOS afforded oxazabicyclic lactol 87 via linear aldehyde 86 in 83% yield (Scheme 14)." The regioselective hydroformylation of 7-amidoallylboronate 88 gave linear aldehyde 89 which was in equilibrium with lactol 90. Removal of the benzyloxycarbonyl (Cbz) group by hydrogenolysis initiated another cascade process, that is, amination-hydro-genation, affording indolizidine 91 in 60% overall yield." ... 

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