9x2- Diels Alder From Myer's Advanced Organic Chemistry-Synthesis Of Complex Molecules.pdf

文档介绍：Myers Asymmetric Diels-Alder Reactions Chem 115
Reviews: Dimenthyl Fumarate:
Oppolzer, W. anic Synthesis; Trost, . and Fleming, I. Eds.; Pergamon:
Oxford, 1991, Vol. 5, pp. 315-399.
O
O
Kagan, H. B.; Riant, O. Chem. Rev. 1992, 92, 1007-1019. CH3
H3C O CH3
OR Et2AlCl
Helmchen, G.; Karge, R.; Weetman, J. In Modern Synthetic Methods; Scheffold, R., Ed.; Springer- H3C
O CO2R
Verlag: Berlin, Heidelberg, 1986, Vol 4, pp. 262-306. RO CH toluene
3 CO2R
O • Lewis Acid(s?) –78 °C
Reilly, M.; Oh, T. Org. Prep. Proced. Int. 1994, 26, 131-158. O CH3 100%, 99% de
Maruoka, K.; Yamamoto, H. In Catalytic Asymmetric Synthesis, Ojima, I., Ed.; Wiley-VCH:
New York, 1993, Chapter 9, pp. 413-440.
Johnson, J. S. Ph. D. Thesis, Harvard University, 1999. • The menthyl auxiliaries exhibit cooperative asymmetric induction in the case of the fumarate ester,
resulting in excellent selectivity for cycloaddition from the indicated face.
Chiral Auxiliaries:
(–)-8-Phenylmenthol:
Diene Lewis Acid Temperature (°C) Yield de (%)
H3C H3C
Ph AlCl3, CH2Cl2
i-Bu2AlCl –40 56 95
H3C O H3C O
CH CH
3 O –55 °C 3
O
AlCl
3 i-Bu2AlCl –20 94 95
CH3
BnO
CH3
Et2AlCl –20 70 96
O O CH3
I BnO
HO AlCl3 25 92 99
OBn OOR
(Intermediate in prostaglandin synthesis)
89%, 97% de
β
• Endo-selective cycloaddition is proposed to occur from the unblocked -face of the s