Categories: C-N Bond Formation >
Synthesis of enamines
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| Synthesis of | |||
| Enaminones |  |
β-Enamino Esters |  |
| α-Ketoenamines |  |
Ketene Aminals |  |
Literature
By employing Pd(OAc)2 and (t-Bu)2PNP(i-BuNCH2CH2)3N
as ligand, a broad range of aryl bromides and chlorides possessing
base-sensitive substituents provide coupling products with bulky aryl amines in
good to excellent yields. An efficient coupling of vinyl bromides with a variety
of amines produces imines and enamines at room temperature.
Ch. V. Reddy, J. V. Kingston, J. G. Verkade, J. Org. Chem., 2008,
73, 3047-3062.
Michael adducts are provided by a reaction of
alkylidene malonates with enamines, which are generated from vinyl bromides and
pyrrolidine by a prior palladium-catalysed C-N bond formation.
M. C. Willis, J. Chauhan, W. G. Whittinham, Org. Biomol. Chem., 2005, 3, 3094-3095.
A NiH-catalyzed strategy for the hydroamidation of alkynes with dioxazolones
allows convenient access to synthetically useful secondary enamides in (E)-anti-Markovnikov
or Markovnikov selectivity. The reaction is viable for both terminal and
internal alkynes and also tolerates a range of functional groups. The presence
of H2O is crucial for high catalyst turnovers.
X. Lyu, J. Zhang, D. Kim, S. Seo, S. Chang, J. Am. Chem. Soc.,
2021, 143, 5867-5877.
A metal-free regio- and stereoselective intermolecular hydroamination of
arylacetylenes with aliphatic secondary amines provides various (E)-enamines
in the presence of ethylene glycol as a solvent. The solvent plays a major role
through hydrogen bonding and proton exchange.
J. Bahri, N. Tanbouza, T. Ollevier, M. Taillefer, F. Monnier, Synthesis, 2019, 51,
2086-2090.
A range of enol triflates can be coupled with amides, carbamates, and
sulfonamides using palladium catalysis. This method allows the synthesis of
enamides, which may not be readily available by other means.
D. J. Wallace, D. J. Klauber, C.-Y. Chen, R. P.
Volante, Org. Lett., 2003, 5, 4749-4752.
A hydroamination of unactivated alkynes with lithium bis(fluorosulfonyl)imide
(LiN(SO2F)2) provides a single regioisomer of a sulfonyl
fluorides in very good yields under mild conditions. This method offers broad
functional group compatibility and delivers the target vinyl fluorosulfonimides
even in gram-scale. Vinyl fluorosulfonimides can be used for the synthesis of
fluorosulfates and diphenyl sulfate.
X. Bai, L. Huang, P. Zhou, H. Xi, J. Hu, Z. Zuo, H. Feng, J. Org. Chem., 2022, 87,
4998-5004.
Vinylsilanes are stereoselectively converted into enamides by a sequence
comprising epoxidation, nucleophilic ring opening of the resulting epoxysilanes
with NaN3, and reduction of the azide, followed by a "one-pot" N-acylation/Peterson
elimination process. This method is distinguished by its wide applicability.
A. Fürstner, C. Brehm, Y. Cancho-Grande, Org. Lett., 2001, 3,
3955-3957.
Vinylsilanes are stereoselectively converted into enamides by a sequence
comprising epoxidation, nucleophilic ring opening of the resulting epoxysilanes
with NaN3, and reduction of the azide, followed by a "one-pot" N-acylation/Peterson
elimination process. This method is distinguished by its wide applicability.
A. Fürstner, C. Brehm, Y. Cancho-Grande, Org. Lett., 2001, 3,
3955-3957.
A palladium-catalyzed carbon-nitrogen bond-forming reaction of anilines and
indoles with propargyl carbonates furnishes 2-amino-1,3-dienes in excellent
yields under mild conditions and shows a broad functional group tolerance. The
resulting 1,3-dienes are of great synthetic interest.
C. Q. O'Broin, P. J. Guiry,
Org. Lett., 2020, 22, 879-883.
Orangoselenium catalysis enables an efficient route to 3-amino allylic alcohols
in excellent regio- and stereoselectivity in the presence of a base. In the
absence of bases α,β-unsaturated aldehydes were formed in excellent yield. The
hydroxy group is crucial for the direct amination.
Z. Deng, J. Wei, L. Liao, H. Huang, X. Zhao, Org. Lett.,
2015,
17, 1834-1837.
Nucleophilic addition of sulfonamides to 1-bromo-1-alkynes provided (Z)-N-(1-bromo-1-alken-2-yl)-p-toluenesulfonamides
in good yield and in a highly regio- and stereoselective manner. A subsequent
reaction in the presence of a palladium catalyst under Heck conditions afforded
substituted pyrroles in good yield.
M. Yamagishi, K. Nishigai, T. Hata, H. Urabe, Org. Lett., 2011,
13, 4873-4875.
An efficient intermolecular trans-selective β-hydroamidation of
ynamides provides (Z)-ethene-1,2-diamide derivatives with excellent
regio- and stereo-selectivities for a wide range of substrates. The reaction
proceeds under basic conditions in the absence of a transition-metal catalyst.
Z. Peng, Z. Zhang, Y. Tu, X. Zeng, J. Zhao, Org. Lett.,
2018, 20, 5688-5691.
Rhodium(II) azavinyl carbenes, which are conveniently generated from
1-sulfonyl-1,2,3-triazoles, undergo a facile, mild, and convergent formal
1,3-insertion into N-H and O-H bonds of primary and secondary amides, various
alcohols, and carboxylic acids to afford a wide range of vicinally
bisfunctionalized (Z)-olefins with perfect regio- and stereoselectivity.
S. Chuprakov, B. T. Worrell, N. Selander, R. K. Sit, V. V. Fokin, J. Am. Chem. Soc., 2014,
136, 195-202.
