A Facile Access to Densely Functionalized Substituted Cyclopentanes and Spiro Cyclopentanes. Carbocation Stabilization Directed Bond Migration in Rearrangement of Cyclobutanes
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
A Facile Access to Densely Functionalized
Substituted Cyclopentanes and Spiro
Cyclopentanes. Carbocation Stabilization
Directed Bond Migration in
Rearrangement of Cyclobutanes
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| Creator |
Haque, Azizul
Ghatak, Anjan Ghosh, Subrata Ghoshal, Nanda |
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| Subject |
Drug Development/Diagnostics & Biotechnology
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| Description |
Substituted cyclopentanes are widely represented in
nature and have served as valuable precursors1 in the
total synthesis of natural products. The cyclopentanone
I having substituents at the 2, 3, and 5 positions as
present in the novel sesquiterpene herbadysidolide II2
and related compounds poses considerable synthetic
challenge. Although much effort has been spent on
annulation of cyclopentane rings3 onto preexisting rings,
little attention has been given to the synthesis of cyclopentanones4
with multiple substitution as represented
by the structure I. Construction of cyclopentanones of
this type through stepwise addition of substituents to
prebuilt cyclopentanone is a lengthy process and is in
general attended with poor regio- and stereoselectivity.
An approach in which substituents are directly generated
during construction of the cyclopentane ring is likely to
have great synthetic importance in terms of selectivity
and step economy. Development of a general methodology
to construct cyclopentanones represented by the
general structure I, thus, became our primary objective.
We anticipate that acid-induced rearrangement5 of the
cyclobutane ring in the tricyclic compound III (R3,R4 )
O) may produce the desired cyclopentanone I provided
1,5-bond migration takes place preferentially over the
1,7-bond. In light of the stereoelectronic requirement6
in the pinacol rearrangement, the 1,7-bond migration
may be competitive. Thus it is of considerable interest
to investigate the rearrangement of the cyclobutane
derivatives III leading to a general route for the direct
synthesis of cyclopentanones with functionalised substituents
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| Date |
1997
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/813/1/JOURNAL_OF_ORGANIC_CHEMISTRY%2C_62(_15)%2C_5211%2D5214_[43].pdf
Haque, Azizul and Ghatak, Anjan and Ghosh, Subrata and Ghoshal, Nanda (1997) A Facile Access to Densely Functionalized Substituted Cyclopentanes and Spiro Cyclopentanes. Carbocation Stabilization Directed Bond Migration in Rearrangement of Cyclobutanes. The Journal of Organic Chemistry, 62 (15). pp. 5211-5214. |
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| Relation |
http://dx.doi.org/10.1021/jo970283m
http://www.eprints.iicb.res.in/813/ |
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