A novel strategy towards aminophosphonic derivatives based on the Diels-Alder cycloaddition: Experimental and theoretical approaches

this review focuses on the regio- and stereoselective synthesis of beta-, gamma-, and delta-aminophosphonic derivatives by combining dienophiles and dienes substituted by phosphono- and amino-groups. The initially formed cyclohexene adducts have been further transformed: chemoselective deprotections of masked P, C, and N functions, double bond oxidation and cleavage. Our Diels-Alder strategy has been successfully applied in asymmetric synthesis thanks to the development of a novel chiral 1-aminodiene designed by computational chemistry. The influence of a phosphonate substituent on reactivity in [4+2] cycloadditions has been theoretically studied

Synthesis of C5-substituted imidazolines

5-(Hydroxymethyl)-3-(t-butyloxycarbonyl)imidazoline 2 was prepared in four steps from 2,3-diaminopropionic acid in 72% overall yield. Mitsunobu reaction with a series of phenol derivatives gave the corresponding 5-(aryloxymethyl)-3-(t-butyloxycarbonyl)imidazolines 8a-1. Phthalimide and N-benzyl trifluoroacetamide also reacted. (C) 2003 Elsevier Ltd. All rights reserved

[4+2] Cycloaddition of 1-aminodienes and 2-substituted vinylphosphonates: application to asymmetric synthesis of 3-amino-5-phosphono-1-cyclohexene derivatives

N-Butadienylsuccinimide (1), iso-propyl N-butadienyl-(S)-pyroglutamate (5) and N-butadienyl-(R)-4-phenyloxazolidin-2-one (6) reacted with vinylphosphonates, vicinally-substituted (2) by electronwithdrawing groups (CO2Me, CN, COMe), to furnish [4+2] cycloadducts (3-4,7-10, and 11-14) in moderate to good yields (40-88%). The reactions were highly selective: regioselectivity of 95-100%, endoselectivity of 75-92% and facial selectivity of 80-95%. The major diastereoisomers were fully characterized by H-1 and C-13 NMR spectroscopy. (C) 2003 Elsevier Science Ltd. All rights reserved