Hantzsch Ester
Diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate

Recent Literature

An efficient and highly enantioselective conjugate transfer hydrogenation of α,β-unsaturated ketones is catalyzed by a salt made from tert-butyl valinate and a recently introduced powerful chiral phosphoric acid catalyst (TRIP).
N. J. A. Martin, B. List, J. Am. Chem. Soc., 2006, 128, 13368-13369.

The use of a chiral imidazolidinone catalyst has provided a new organocatalytic strategy for the enantioselective reduction of β,β-substituted α,β-unsaturated aldehydes to generate β-stereogenic aldehydes using ethyl Hantzsch ester as the hydrogen source. In addition, an acceleration of E-Z isomerization prior to selective E-olefin reduction allows the use of geometrically impure enals in this operationally simple protocol.
S. G. Ouellet, J. B. Tuttle, D. W. C. MacMillan, J. Am. Chem. Soc., 2005, 7, 32-33.

α-Imino esters derived from aryl and alkyl keto esters could be reduced to the corresponding α-amino esters in excellent yields and in high enantiomeric excesses using 5 mol-% of a chiral phosphoric acid as catalyst, Hantzsch ester as hydride donor, and toluene as solvent.
G. Li, Y. Liang, J. C. Antilla, J. Am. Chem. Soc., 2007, 129, 5830-5831.

A thiourea-catalyzed transfer hydrogenation of various aromatic as well as aliphatic aldimines through hydrogen-bonding activation with Hantzsch 1,4-dihydropyridine as the hydrogen source gives the respective amines under acid- and metal-free reaction conditions.
Z. Zhang, P. R. Schreiner, Synlett, 2007, 1455-1457.

A biomimetic direct reductive amination of ketones relies on selective imine activation by hydrogen bond formation with thiourea as hydrogen bond donor and utilizes the Hantzsch ester for transfer hydrogenation. The method allows the efficient synthesis of structurally diverse amines.
D. Menche, J. Hassfeld, J. Li, G. Menche, A. Ritter, S. Rudolph, Org. Lett., 2006, 8, 741-744.

A hydrogen-bond-catalyzed, acid- and metal-free direct reductive amination of aldehydes uses thiourea as organocatalyst and the Hantzsch ester for transfer-hydrogenation. This methods allows for the high-yielding synthesis of diverse amines.
D. Menche, F. Arikan, Synlett, 2006, 841-844.

An achiral amine in combination with a catalytic amount of a chiral Brønsted acid can accomplish an aldol addition-dehydration-conjugate reduction-reductive amination with 2,6-diketones to provide cyclohexylamines as potential intermediates of pharmaceutically active compounds in good yields and excellent enantioselectivities.
J. Zhou, B. List, J. Am. Chem. Soc., 2007, 129, 7498-7499.

A highly efficient and highly enantioselective Hantzsch ester mediated conjugate transfer hydrogenation of β,β-disubstituted nitroolefins is catalyzed by a Jacobsen-type thiourea catalyst.
N. J. A. Martin, L. Ozores, B. List, J. Am. Chem. Soc., 2007, 129, 8976-8977.