TY - JOUR
T1 - Enantiopure 4-oxazolin-2-ones and 4-methylene-2-oxazolidinones as chiral building blocks in a divergent asymmetric synthesis of heterocycles
AU - Santoyo, Blanca M.
AU - González-Romero, Carlos
AU - Zárate-Zárate, Daniel
AU - Hernández-Benitez, R. Israel
AU - Pelayo, Vanessa
AU - Barrera, Edson
AU - Escalante, Carlos H.
AU - Fuentes-Benites, Aydeé
AU - Martínez-Morales, Guadalupe
AU - López, Julio
AU - Vázquez, Miguel A.
AU - Delgado, Francisco
AU - Jiménez-Vázquez, Hugo A.
AU - Tamariz, Joaquín
N1 - Publisher Copyright:
© 2019 Wiley Periodicals, Inc.
PY - 2019/9
Y1 - 2019/9
N2 - Enantiopure 3-((R)- and 3-((S)-1-phenylethyl)-4-oxazoline-2-ones were evaluated as chiral building blocks for the divergent construction of heterocycles with stereogenic quaternary centers. The N-(R)- or N-(S)-1-phenylethyl group of these compounds proved to be an efficient chiral auxiliary for the asymmetric induction of the 4- and 5-positions of the 4-oxazolin-2-one ring through thermal and MW-promoted nucleophilic conjugated addition to Michael acceptors and alkyl halides. The resulting adducts were transformed via a cascade process into fused six-membered carbo- and heterocycles. The structure of the reaction products depended on the electrophiles and reaction conditions used. Alternative isomeric 4-methylene-2-oxazolidinones served as chiral precursors for a versatile and divergent approach to highly substituted cyclic carbamates. DFT quantum calculations showed that the formation of bicyclic pyranyl compounds was generated by a diastereoselective concerted hetero-Diels-Alder cycloaddition.
AB - Enantiopure 3-((R)- and 3-((S)-1-phenylethyl)-4-oxazoline-2-ones were evaluated as chiral building blocks for the divergent construction of heterocycles with stereogenic quaternary centers. The N-(R)- or N-(S)-1-phenylethyl group of these compounds proved to be an efficient chiral auxiliary for the asymmetric induction of the 4- and 5-positions of the 4-oxazolin-2-one ring through thermal and MW-promoted nucleophilic conjugated addition to Michael acceptors and alkyl halides. The resulting adducts were transformed via a cascade process into fused six-membered carbo- and heterocycles. The structure of the reaction products depended on the electrophiles and reaction conditions used. Alternative isomeric 4-methylene-2-oxazolidinones served as chiral precursors for a versatile and divergent approach to highly substituted cyclic carbamates. DFT quantum calculations showed that the formation of bicyclic pyranyl compounds was generated by a diastereoselective concerted hetero-Diels-Alder cycloaddition.
KW - (R)- and (S)-1-phenylethylamine
KW - 4-methylene-2-oxazolidinones
KW - 4-oxazolin-2-ones
KW - hetero-Diels-Alder reaction
KW - microwave irradiation
UR - http://www.scopus.com/inward/record.url?scp=85069892468&partnerID=8YFLogxK
U2 - 10.1002/chir.23109
DO - 10.1002/chir.23109
M3 - Artículo
C2 - 31318100
AN - SCOPUS:85069892468
SN - 0899-0042
VL - 31
SP - 719
EP - 749
JO - Chirality
JF - Chirality
IS - 9
ER -