One-pot reaction of 2-formylbenzoates, hexamethyldisilazane, and diethyl phosphite in the presence of Yb(OTf) 3 : Synthesis of 3-phosphonate phthalides

One-Pot Catalytic Synthesis of α-Tetrasubstituted Amino Acid Derivatives via In Situ Generation of N-Unsubstituted Ketimines

A one-pot catalytic synthesis of α-tetrasubstituted amino acid derivatives via in situ generation of N-unsubstituted ketimines is reported. Because of the irreversible formation of N-unsubstituted ketimines, the yields were higher than those generated under the conventional one-pot reaction conditions. This process prevents the need to isolate unstable N-unsubstituted ketimines with alkyl substituents and streamlines the synthesis of highly congested α-amino acid derivatives.

AgNTf2 catalyzed cycloaddition of N-acyliminium ions with alkynes for the synthesis of the 3,4-dihydro-1,3-oxazin-2-one skeleton

A catalyzed process for the synthesis of the 4,6-substituted 3,4-dihydro-1,3-oxazin-2-one skeleton has been developed through cycloaddition of in situ generated acyliminium intermediates with alkynes. A range of chain N,O-acetals and terminal alkynes were amenable for this mild transformation. As a result, a series of desired cycloaddition products were obtained in moderate to good yields.