Enantioselective Synthesis of (+)-Obolactone Based on a Symmetry-Breaking Wacker Monooxidation of a Diene
摘要:
A concise synthesis of the dihydro-alpha-pyrone/dihydro-gamma-pyrone natural product (+)-obolactone (13) is disclosed. The dienediol acetonide 23 (>= 97% ee) was obtained from 1,5-dichloropentane-2,4-dione in four steps. A Wacker monooxidation of 23 furnished the monoketone 24 in 64% yield. The OH group of the ensuing dihydro-gamma-pyrone 31 was esterified under Mitsunobu conditions with cinnamic acid (-> 80% inversion and 20% retention of configuration). A ring-closing metathesis formed the dihydro-alpha-pyrone moiety of the target in the terminating step.
Stereoselective total synthesis of obolactones and 7′,8′-dihydroobolactones
作者:Deepak Saini、Praveen Kumar、Rodney A. Fernandes
DOI:10.1039/d1nj03990c
日期:——
A concise stereoselectivetotalsynthesis of two diastereomeric obolactones and 7′,8′-dihydroobolactones has been achieved using a metal-free catalytic δ-hydroxyalkynone rearrangement, which could provide the required dihydro-γ-pyrone moiety. The desired first stereogenic center was installed through the chiral pool material, L-aspartic acid. Next, the allylation reaction was strategically utilized