Synthesis of the cores of hypocrellin and shiraiachrome: diastereoselective 1,8-diketone aldol cyclization.
Intramolecular 1,8-diketone aldol reactions were studied as a tool for the construction of the seven-membered rings of hypocrellin and shiraiachrome. Conditions were identified to obtain the relative stereochemistries present in the two natural products with excellent diastereoselectivity. In addition, a nine-membered ring congener, which has yet to be observed in nature, formed with high selectivity when a hindered amine was used in conjunction with silazide bases.
O'Brien
Erin M
EM
Department of Chemistry, Roy and Diana Vagelos Laboratories, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Li
Jingxian
J
Carroll
Patrick J
PJ
Kozlowski
Marisa C
MC
D000447:Aldehydes / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D010569:Perylene / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D019800:Phenol; D011809:Quinones / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D000447:Aldehydes; D007659:Ketones; D011809:Quinones; C075921:Shiraiachrome A; D019800:Phenol; D010569:Perylene; C116609:3-hydroxybutanal; C048388:hypocrellin A