Ceric ammonium nitrate impregnated on silica gel in the removal of the tert-butoxycarbonyl group

Abstract

The tert-butoxycarbonyl group was efficiently (80-99% yields) removed from an amino, hydroxy, or mercapto functionality in organic compounds by use of 0.20 equiv of Ce(NH 4 ) 2 (NO 3 ) 6 in acetonitrile at reflux. Application of the solid-supported reagent involving the use of 0.20 equiv of Ce(NH 4 ) 2 (NO 3 ) 6 impregnated on silica gel in toluene at reflux gave the deprotected products in 90-99% yields. These reactions likely proceed through an electron transfer process.

Cerium(IV) Ammonium Nitrate as a Catalyst in Organic Synthesis

“…The same authors also observed the removal of t-Boc group using silica gel supported CAN as a catalyst, finding that this modification of their method considerably reduced the reaction time. 97…”

Mild and Neutral Deprotections Catalyzed by Cerium(IV) Ammonium Nitrate

“…While CAN was already a well-known reagent for the oxidative deprotection of S,S- and O,S-acetals and ketals, the oxidative cleavage of tert -butyldimethylsilyl ethers and the removal of tert -Boc groups, to the best of our knowledge, it had not been used to unmask acetals and ketals. The surprisingly rapid and efficient deprotection of ketal 1 prompted us to investigate in greater detail the scope and limitations of this novel reaction.…”

Cerium(IV)‐Mediated Carbon‐Carbon Bond Formation for the Synthesis of Spirodienone Lactams

“…The low yield observed for this cyclisation is due to the competitive cleavage of the Boc group with the CAN leading to the decomposition of the α-AAP 13 a. [29] To avoid this side reaction, the α-AAP 13 b was prepared in a comparable yield. Treatment of the latter with CAN yielded the expected spirocyclic compound 14 b in an improved 51 % yield as expected.…”

“…Next, the [2,3]‐sigmatropic rearrangement took place after the addition of diethyl chlorophosphite on the ynamido‐alcohol 12 a and the resulting Boc protected α‐AAP 13 a was treated with CAN in a mixture of acetonitrile and water (2 : 1) to provide the expected spirodienone lactam 14 a in a low 36 % yield. The low yield observed for this cyclisation is due to the competitive cleavage of the Boc group with the CAN leading to the decomposition of the α‐AAP 13 a [29] . To avoid this side reaction, the α‐AAP 13 b was prepared in a comparable yield.…”