Synthesis of protected primary amines
A low catalyst loading of [Cp*IrCl2]2 in the presence of t-BuOK enables a simple and versatile N-alkylation of sulfonamides with various alcohols based on a catalytic hydrogen transfer reaction. Various N-alkylated sulfonamides were prepared in good to excellent yields. Key catalytic species is a sulfonylimido-bridged unsaturated diiridium complex [(Cp*Ir)2(μ-NTs)2].
M. Zhu, K.-i. Fujita, R. Yamaguchi, Org. Lett., 2010, 12, 1336-1339.
The direct amination of alkyl and aryl pinacol boronates with lithiated methoxyamine provides aliphatic and aromatic amines, stereospecifically, and without preactivation of the boronate substrate.
S. N. Mlynarski, A. S. Karns, J. P. Morken, J. Am. Chem. Soc., 2012, 134, 16449-16451.
Half-sandwich ruthenium complexes activate terminal alkynes toward anti-Markovnikov hydration and reductive hydration under mild conditions. Propargylic alcohols can be converted to 1,3-diols in high yield and with retention of stereochemistry at the propargylic position. The method is also amenable to formal anti-Markovnikov reductive amination and oxidative hydration reactions to access linear amines and carboxylic acids, respectively.
M. Zeng, S. B. Herzon, J. Org. Chem., 2015, 80, 8604-8618.
A three-component condensation of aldehydes, benzyl carbamate and allyltrimethylsilane, which affords corresponding protected homoallylic amines in excellent yields, is catalyzed by iodine.
P. Phukan, J. Org. Chem., 2004, 69, 4005-4006.
An efficient palladium-catalyzed asymmetric amination of 2,3-allenyl phosphates with nitrogen nucleophiles such as amines, hydroxylamines, and imides can be performed in presence of SEGPHOS or MeOBIPHEP ligand, affording the corresponding optically active 1-aminated derivatives with high enantiomeric excess.
Y. Imada, M. Nishida, K. Kutsuwa, S.-I. Murahashi, T. Naota, Org. Lett., 2005, 7, 5837-5839.
Iridium-catalyzed allylation of potassium trifluoroacetamide or the highly reactive ammonia equivalent lithium di-tert-butyliminodicarboxylate forms a range of conveniently protected, primary, α-branched allylic amines in high yields, high branched-to-linear regioselectivities, and high enantiomeric excess.
M. J. Pouy, A. Leitner, D. J. Weix, S. Ueno, J. F. Hartwig, Org. Lett., 2007, 9, 3949-3952.
Hydroamination of substituted allenes with benzyl carbamate catalyzed by (NHC)AuCl and AgOTf in dioxane led to isolation of allylic carbamates in good yield as single regio- and diastereomers.
R. E. Kinder, Z. Zhang, R. A. Widenhoefer, Org. Lett., 2008, 10, 3157-3159.
A mild, gold(I)-catalyzed hydroamination of 1,3-dienes is reported. Various carbamates and sulfonamides add to conjugated dienes to affort protected allylic amines in good to high yields.
C. Brouwer, C. He, Angew. Chem. Int. Ed., 2006, 45, 1744-1747.
Addition of sulfonamides to alkenes and conjugated dienes can be carried out using a low catalytic amount of (triphenyl phosphite)gold(I) chloride and silver triflate under thermal or microwave conditions and at r.t. in the case of dienes. Terminal alkenes undergo regioselective hydroamination at the internal carbon atom and dienes at the less substituted double bond.
X. Giner, C. NŠjera, Org. Lett., 2008, 10, 2919-2922.
Copper(II) trifluoromethanesulfonate catalyzed a mild amidation of cyclic ethers with iminoiodanes with good yields and selectivity. A subsequent reductive ring-opening of the tosylamidated products gives α,ϖ-amino alcohols.
L. He, J. Yu, J. Zhang, X.-Q. Yu, Org. Lett., 2007, 9, 2277-2280.
An efficient amidation reaction of saturated C-H bonds catalyzed by a unique disilver(I) complex is reported. The reaction is stereospecific and practical for the construction of amine-containing molecules.
Y. Cui, C. He, Angew. Chem. Int. Ed., 2004, 43, 4210-4212.
Benzylic hydrocarbons are selectively converted to the corresponding sulfonamides by the [Cu(CH3CN)4]PF6-catalyzed reaction with anhydrous TolSO2NNaCl (chloramine-T). Under the same conditions, representative ethers and olefins are also amidated.
R. Bhuyan, K. M. Nicholas, Org. Lett., 2007, 9, 3957-3959.
A highly chemoselective PPh3-catalyzed three-component reaction of an imine, alkyl vinyl ketone, and phthalimide or succinimide gives various highly functional adducts with high diastereoselectivities via aza-Morita-Baylis-Hillman reactions of aryl-substituted imines and alkyl vinyl ketones followed by Michael additions of imides and then epimerization.
S.-e. Syu, Y.-T. Lee, Y.-J. Jang, W. Lin, J. Org. Chem., 2011, 76, 2888-2891.
A new procedure for aminobromination of olefins gives vicinal bromoamine derivatives in high yields using Cu, Mn, or V catalysts with p-toluenesulfonamide as nitrogen source and N-bromosuccinimide (NBS) as bromine source. Excellent regio- and stereoselectivity is shown for different olefinic substrates as well as transition metal catalysts.
V. V. Thakur, S. K. Talluri, A. Sudalai, Org. Lett., 2003, 5, 861-864.