1997 Fiscal Year Final Research Report Summary
Studies on Remote Asymmetric Induction in Cycloaddition Reactions using Novel Chiral Sulfoxides
| Project/Area Number |
08672434
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Chemical pharmacy
|
|---|
| Research Institution | GIFU PHARMACEUTICAL UNIVERSITY |
|---|
Principal Investigator |
ARAI Yoshitsugu GIFU PHARMACEUTICAL UNIVERSITY,FACULTY OF PHARMCEUTICAL SCIENCES,ASSOCIATE PROFESSOR, 薬学部, 助教授 (10115157)
|
|---|
| Project Period (FY) |
1996 – 1997
|
| Keywords | chiral sulfoxide / Diels-Alder reaction / asymmetric reduction / remote asymmetric induction / alpha, beta-unsaturated ketone / Lewis acid / dienophile / diastereoselective |
|---|
| Research Abstract |
Three types of chiral sulfoxides having a 5-membered aromatic heterocycle (furan, thiophene and pyrrole) were synthesized and high levels of diastereoselectivity in addition reactions were observed.
1.Stereoselective reduction
Reduction of chiral 3-(p-tolylsulfinyl)-2-thienyl alkyl (and aryl) keones with diisobutylaluminum hydride afforded the corresponding (S)-thienylcarbinols as the major product, while the similar reduction in the presence of a Lewis acid or lithium tri-sec-butylborohydride (L-Selectride^<<encircledR>>) reduction afforded (R)-alcohols as the major isomer.
2.Stereoselective hetero Diels-Alder reaction
A lanthanide triflate-promoted hetero Diels-Alder reaction of chiral 3-(p-tolylsulfinyl) furaldehyde with Danishefsky's diene proceeded to give the adduct with excellent distereoselectivity.
3.Stereoselective Diels-Alder reaction
2-Futyl and 2-thienyl alpha, beta-enones, bearing a chiral p-tolylsulfinyl group in the heterocycle, served as an efficient dienophile in the Diels-Alder reaction, where the catalytic use of aluminium chloride or a lanthanide triflate effected these cycloadditions with cyclopentadiene affording the endo adduct with high diastereoselectivity, ranging from 91% to 98%. Similarly the enone to which a chiral p-tolylsulfinyl pyrrole moiety was incorporated also underwent the cycloaddition with up to 89% diastereoisomeric excess in the presence of 1 eqiuv. of the Lewis acid. In particular for the Diels-Alder reaction, the auxiliary (i.e.the sulfinyl pyrrole) was recovered after use without any loss of optical purity.
|
