Synthesis of the four d,l-pairs of 2-amino-3-phenylnorbornane-2-carboxylic acids II. The use of 5(4H)-oxazolones as dienophiles.

Asymmetric Synthesis of 2-Amino-3-hydroxynorbornene-2-carboxylic Acid Derivatives

“…However, this synthetic approach suffered from a potential drawback. In fact, it is well-known that 3-substituted aminoacrylates do not react with dienes in the Diels−Alder reaction . To verify the feasibility of this method and to ascertain the reactivity of the double bond, the achiral methyl 2-benzoylamino-3-ethoxycarbolyloxyacrylate 12a was first synthesized.…”

Organic Reactions in Aqueous Media with a Focus on Carbon−Carbon Bond Formations: A Decade Update

“…The Diels-Alder reaction between oxazolone and cyclopentadiene was investigated by Cativiela in water (eq 205). 825 Although the reaction is very slow, the (E)-5(4H)-oxazolone reacted with cyclopentadiene in an aqueous media for 6 days at room temperature to form the corresponding spiroxazolones in a 95% yield. The cycloadducts are then readily converted into amino-norbornane carboxylic acids.…”

Conformationally rigid cyclic α-amino acids in the design of peptidomimetics, peptide models and biologically active compounds

“…Numerous CRA with the norbornane cage have been prepared. In addition to the unsubstituted acid 144, various functionalised derivatives 146 ± 155 (which represent analogues of phenylalanine, 208,209,217 tyrosine, 217 aspartic acid, 211,212 serine, 213 methionine, 219 glutamic acid 211, 219 ± 221 ), including polyhydroxy-compounds 156a ± d 216 have been prepared. All of these compounds are fully w-rigid (except for 152, which is w 1 -rigid).…”