A novel Michael-initiated ring closure reacton involving allylic chlorosulfone (2) and γ-alkoxy-α,β-ynoates to afford 4- methylenecyclopentenecarboxylates is reported, while with γ-alkylynoates no reaction occurred. With chiral phenyl ynoates 4, the reaction proceeds by 1,3-asymmetric induction and leads further to a nonracemic annulated α,β- butenolide (7). (C) 2000 Elsevier Science Ltd.
|Number of pages||5|
|State||Published - 15 Jul 2000|
Bibliographical noteFunding Information:
The authors wish to thank the US–Israel Science Foundation and the Marcus Center for Pharmaceutical and Medicinal Chemistry at Bar-Ilan University for financial support, and Dr. Hugo E. Gottlieb for his valuable help in NMR analysis.
- Asymmetric induction
- Lithium ion chelation
- Michael reactions