Preparation of R-(+)-3,4-dimethoxybenzyl 2-methoxy-1-naphthyl sulfoxide and diastereoselective addition of lithiated anion of this reagent to cyclic nitrone. Asymmetric synthesis of optical pure isoquinoline alkaloids

Article abstract of DOI:10.1080/10426500008042106

The addition of the lithium carbanion of (R)-(+)-3,4-dimethoxybenzyl 2-methoxy-1-naphthyl sulfoxide 3 to cyclic nitrone 4, under kinetically controlled conditions gave isoquinoline sulfoxide derivatives 5 and 6 in high diastereoselectivities. Under equilibrium controlled conditions poor diastereoselectivity results. The chiral (R)-(+)-3,4-dimethoxybenzyl 2-methoxy-1-naphthyl sulfoxide 3 was easily prepared by the reaction of 3,4-dimethoxybenzylmagnesium chloride 2 with (-)-(S) menthyl 2-methoxy-naphthalene sulfinate 1 in dry benzene. This methodology allows for the synthesis of the isoquinoline alkaloid (R)-(-)-norlaudanosine 8 in three efficient synthetic steps.

Full text of DOI:10.1080/10426500008042106

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Phosphorus, Sulfur, and Silicon
and the Related Elements
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PREPARATION OF R-(+)-3,4-
DIMETHOXYBENZYL 2-
METHOXY-1-NAPHTHYL
SULFOXIDE AND
DIASTEREOSELECTIVE ADDITION
OF LITHIATED ANION OF THIS
REAGENT TO CYCLIC NITRONE.
ASYMMETRIC SYNTHESIS OF
OPTICAL PURE ISOQUINOLINE
ALKALOIDS
A. R. Hajipour a & M. Hantehzadeh a
a Pharmaceutical Research Laboratory, Collage of
Chemistry Isfahan University of Technology, Isfahan,
IR, Iran
Published online: 04 Oct 2006.
To cite this article: A. R. Hajipour & M. Hantehzadeh (2000): PREPARATION
OF R-(+)-3,4-DIMETHOXYBENZYL 2-METHOXY-1-NAPHTHYL SULFOXIDE AND
DIASTEREOSELECTIVE ADDITION OF LITHIATED ANION OF THIS REAGENT TO CYCLIC
NITRONE. ASYMMETRIC SYNTHESIS OF OPTICAL PURE ISOQUINOLINE ALKALOIDS,
Phosphorus, Sulfur, and Silicon and the Related Elements, 161:1, 181-189
To link to this article: http://dx.doi.org/10.1080/10426500008042106
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