Biomimetic Total Synthesis of Angiopterlactone B and Other Potential Natural Products
Tharun K Kotammagari1, Rajesh G Gonnade1, Asish K Bhattacharya1
1Division of Organic Chemistry, ‡Academy of Scientific and Innovative Research, and §Centre for Material Characterization, CSIR-National Chemical Laboratory , Dr. Homi Bhabha Road, Pune 411 008, India.
Abstract:
A one-pot biomimetic synthesis of (-)-angiopterlactone B and its enantiomer (+)-angiopterlactone B has been accomplished via TBAF-catalyzed tandem ring contraction followed by oxa-Michael/Michael addition sequence. Comparison of specific optical rotations, absolute configurations, and CD spectra of natural, synthesized (-)-angiopterlactone B and (+)-angiopterlactone B unequivocally proves that the isolated angiopterlactone B must be levorotatory. Synthesis of hitherto undiscovered natural products 18 and 20 and analogues of angiopterlactone B demonstrate the versatility of this method.
