TY - JOUR
T1 - Nucleophilic additions on acetyldioxanes derived from (−)-(1R)-myrtenal used as chiral auxiliaries
T2 - substituent effects on the stereochemical outcome
AU - Becerra-Martínez, Elvia
AU - Ayala-Mata, Francisco
AU - Velázquez-Ponce, Pedro
AU - Medina, Manuel E.
AU - Jiménez-Vazquez, Hugo A.
AU - Joseph-Nathan, Pedro
AU - Zepeda, L. Gerardo
N1 - Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017/10/15
Y1 - 2017/10/15
N2 - The synthesis of acetyldioxanes 4 and 9a starting from (−)-(1R)-myrtenal is described. The products were treated with a representative series of nucleophilic reagents (RMgX, RLi, NaBH4 and LiAlH4) to assess the effect of the substituent at C-3 on the stereochemical outcome. It was observed that the nucleophiles preferred the re-face of the C[dbnd]O group when the equatorial substituent at C-3 was a methyl group, whereas a phenyl group at the same position induced the addition through the si-face, thus allowing access to either desired stereochemistry of a final product. This behavior suggests that the formation of the expected Cram-chelated coordination complex takes a coplanar orientation with the C-3 equatorial substituent. Moreover, Grignard reagents were the most stereoselective nucleophiles. The stereochemistry of the addition was established by X-ray diffraction and chemical correlation.
AB - The synthesis of acetyldioxanes 4 and 9a starting from (−)-(1R)-myrtenal is described. The products were treated with a representative series of nucleophilic reagents (RMgX, RLi, NaBH4 and LiAlH4) to assess the effect of the substituent at C-3 on the stereochemical outcome. It was observed that the nucleophiles preferred the re-face of the C[dbnd]O group when the equatorial substituent at C-3 was a methyl group, whereas a phenyl group at the same position induced the addition through the si-face, thus allowing access to either desired stereochemistry of a final product. This behavior suggests that the formation of the expected Cram-chelated coordination complex takes a coplanar orientation with the C-3 equatorial substituent. Moreover, Grignard reagents were the most stereoselective nucleophiles. The stereochemistry of the addition was established by X-ray diffraction and chemical correlation.
UR - http://www.scopus.com/inward/record.url?scp=85030755734&partnerID=8YFLogxK
U2 - 10.1016/j.tetasy.2017.07.008
DO - 10.1016/j.tetasy.2017.07.008
M3 - Artículo
SN - 0957-4166
VL - 28
SP - 1350
EP - 1358
JO - Tetrahedron Asymmetry
JF - Tetrahedron Asymmetry
IS - 10
ER -