Beilstein J. Org. Chem.2016,12, 1608–1615, doi:10.3762/bjoc.12.157
-1 Hirokoshingai, Kure, Hiroshima 737-0112, Japan 10.3762/bjoc.12.157 Abstract An effective synthesis for syn-β-lactams was achieved using a Rh-catalyzed reductiveMannich-typereaction. A rhodium–hydride complex (Rh–H) derived from diethylzinc (Et2Zn) and a Rh catalyst was used for the 1,4
direct synthesis of β-lactams by reductive Mannich-type reactions [14][18][19][20][21]. We recently reported a reductiveMannich-typereaction using a combination of RhCl(PPh3)3 and Et2Zn to give the corresponding syn-β-lactams from α,β-unsaturated esters and imines in good to excellent yields together
. However, some of the reactions using β-substituted α,β-unsaturated esters did not afford the products or gave the products in very low yield (Scheme 2). Herein, we report an expansion for our previous reductiveMannich-typereaction and mechanistic studies for the stereoselectivity of this reaction
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Graphical Abstract
Scheme 1:
The synthesis of syn-β-lactams using a reductive Mannich-type reaction.