Herein we describe the first synthetic efforts toward the total synthesis of isodaphlongamine H, a calyciphylline B-type alkaloid. The strategy employs a chemoenzymatic process for the preparation of a functionalized cyclopentanol with a quaternary center. This molecule is elaborated to form an enantiopure 1-aza-perhydrocyclopentalene core, representing rings A and E of all calyciphylline B-type alkaloids. Further transformations involve the formation of a cyclic enaminone, 1,4-conjugate addition with a cyclopentenyl subunit, and intramolecular aldol cyclization to achieve a pentacyclic intermediate, ultimately forming isodaphlongamine H in a total of 24 steps from the commercially available compound 2-carbethoxycyclopentanone. Isodaphlongamine H exhibits promising inhibitory activity against a panel of human cancer cell lines.

A highly stereocontrolled total synthesis of (-)-yaequinolone J1 and (+)-yaequinolone J2 was accomplished using an Evans auxiliary to establish a syn-diol unit in an acyclic appendage to a preformed benzopyran core bearing a homoprenyl group. The first total synthesis of a complex member of this family of 3,4-dioxygenated 3,4-dihydro 4-aryl quinolin-2-(1 H)-ones also allowed the assignment of absolute stereochemistry, thereby suggesting the same for several members of this family of biogenetically related alkaloids hitherto reported with relative configurations of stereogenic carbons for some and absolute assignments relying on empirical data for others.

Herein we describe the first synthetic efforts toward the total synthesis of isodaphlongamine H, acalyciphylline Btype alkaloid. The strategy employs achemoenzymatic process for the preparation of af unctionalizedc yclopentanol with aq uaternary center.T his molecule is elaborated to form an enantiopure 1-aza-perhydrocyclopentalene core,r epresenting rings Aa nd Eo fa ll calyciphylline B-type alkaloids.F urther transformations involve the formation of ac yclic enaminone, 1,4-conjugate addition with ac yclopentenyl subunit, and intramolecular aldol cyclization to achieveapentacyclic intermediate,u ltimately forming isodaphlongamine Hi n atotal of 24 steps from the commercially available compound 2-carbethoxycyclopentanone.I sodaphlongamine He xhibits promising inhibitory activity against ap anel of human cancer cell lines.

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