Stereoselective total synthesis of (+)-cryptofolione and (+)-goniothalamin

The stereoselective total synthesis of two naturally occurring α-pyrone derivatives (+)-cryptofolione and (+)-goniothalamin has been accomplished via a common intermediate. The synthetic sequence involves the asymmetric reduction of a propargyl ketone and olefin cross-metathesis as the key reactions.

Figure optionsDownload as PowerPoint slide

(R)-5-(4-Methoxybenzyloxy)-1-phenylpent-1-yn-3-olC19H20O3[α]D25=+50.5 (c 1.5, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R)

(R,E)-5-(4-Methoxybenzyloxy)-1-phenylpent-1-en-3-olC19H22O3[α]D25=+4.65 (c 1.75, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R,1E)

(R,E)-5-(4-Methoxybenzyloxy)-1-phenylpent-1-en-3-yl acetateC21H24O4[α]D25=+24.6 (c 0.8, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R,1E)

(R,E)-5-Hydroxy-1-phenylpent-1-en-3-yl acetateC13H16O3[α]D25=+17.3 (c 1.15, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R,1E)

(3R,5S,1E)-5-Hydroxy-1-phenylocta-1,7-dien-3-yl acetateC16H20O3[α]D25=+25.1 (c 0.15, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (3R,5S,1E)

(1E,3R,5S,7E)-5-Hydroxy-8-((R)-6-oxo-3,6-dihydro-2H-pyran-2-yl)-1-phenylocta-1,7-dien-3-yl acetate)C21H24O5[α]D25=+7.7 (c 0.4, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (1E,3R,5S,7E,6R)

(5R,2Z,6E)-Methyl 5-acetoxy-7-phenylhepta-2,6-dienoateC16H18O4[α]D25=+6.1 (c 1.45, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (5R,2Z,6E)