Synthesis of cyclic amines
An efficient method for the N-heterocyclization of primary amines with diols catalyzed by a Cp*Ir complex was developed. A variety of five-, six-, and seven-membered cyclic amines were synthesized in good to excellent yields.
K.-I. Fujita, T. Fujii, R. Yamaguchi, Org. Lett., 2004, 6, 3525-3528.
Microwave heating enables a Borrowing Hydrogen strategy to form C-N bonds from alcohols and amines, removes the need for solvent and reduces the reaction times, while the results are comparable with those using thermal heating.
A. J. A. Watson, A. C. Maxwell, J. M. J. Williams, J. Org. Chem., 2011, 76, 2328-2331.
A one-pot synthesis of nitrogen-containing heterocycles from alkyl dihalides and primary amines and hydrazines occurs under microwave irradiation via a simple and efficient cyclocondensation in an alkaline aqueous medium.
Y. Ju, R. S. Varma, J. Org. Chem., 2006, 71, 135-141.
A mild, effective gold(I)-catalyzed hydroamination of unactivated olefins to form protected nitrogen heterocycles has been developed. The substrate scope is broader than in reactions realized with late-transition-metal catalyst systems.
X. Han, R. A. Widenhoefer, Angew. Chem. Int. Ed., 2006, 45, 1747-1749.
Optically enriched N-fused bicyclic amides and small- and medium-ring unsaturated cyclic amines can be synthesized in up to 98% ee through Mo-catalyzed desymmetrization of readily available achiral polyene substrates. The effects of catalyst structure, olefin substitution, positioning of Lewis basic functional groups and ring size are examined and discussed in detail.
E. S. Sattely, G. Alexander Cortez, D. C. Moebius, R. R. Schrock, A. H. Hoveyda, J. Am. Chem. Soc., 2005, 127, 8526-8533.
ROM-RCM of cyclobutenylmethylamines having an alkyne moiety in a tether afforded isoquinoline derivatives in good yields using a second-generation Grubbs catalyst.
M. Mori, H. Wakamatsu, K. Tonogaki, R. Fujita, T. Kitamura, Y. Sato, J. Org. Chem., 2005, 70, 1066-1069.
The GaCl3-catalyzed skeletal reorganization of enynes is simple and provides a diverse range of dienes in good to high yields. The reaction of enynes proceeds in a stereospecific manner with respect to the geometry of the olefin moiety.
N. Chatani, H. Inoue, T. Kotsuma, S. Murai, J. Am. Chem. Soc., 2002, 124, 10294-10295
An efficient and regioselective Yb(OTf)3-promoted palladium-catalyzed oxidative cyclization of γ-heteroalkenyl β-keto amides has been developed. Under simple aerobic condition, various six-, seven-, and eight-membered-ring N- and O-heterocycles were obtained in excellent yield.
K.-T. Yip, J.-H. Li, O.-Y. Lee, D. Yang, Org. Lett., 2005, 7, 5717-5719.
Diastereoselective and Enantioselective Construction of Aza-Heterocycles