Xylochemistry--Making Natural Products Entirely from Wood.

The first total synthesis of the dimeric berberine alkaloid ilicifoline (ilicifoline B) is reported. Its carbon skeleton is constructed from ferulic acid, veratrole, and methanol. The synthesis reported herein employs starting materials solely derived from wood. The natural product is thus constructed entirely from renewable resources. The same strategy is applied to a formal total synthesis of morphinan alkaloids. The use of wood-derived building blocks (xylochemicals) instead of the conventional petrochemicals represents a sustainable alternative to classical synthetic approaches.

Phosphine-substituted sterically encumbered pyrrolyl ligands - synthesis and reactivity studies.

The sterically encumbered pyrrolyl KPyr(tBu2) (1-K, Pyr(tBu2) = 2,5-(Me3C)2C4H2N) reacts with PCl3, (iPr)2PCl and Ph2PCl exclusively at the C3-position to yield a series of phosphine-substituted pyrroles HPyr(tBu2R) (R = PCl2 (2-H), (iPr)2P (4-H) and Ph2P (5-H)). Pyrrole 2-H can further be functionalized with MeLi (3 equiv.) to yield LiPyr(tBu2PMe2) (3-Li). The coordination chemistry of these phosphine-substituted pyrroles was explored and the resulting complexes were characterized by various spectroscopic techniques and in some cases using single crystal X-ray diffraction. The neutral pyrroles 4-H and 5-H react cleanly with [Mo(CO)6] to form the κP-coordinate complexes 4-H-Mo(CO)5 and 5-H-Mo(CO)5, respectively. IR spectroscopy of these complexes shows that C3-substitution barely changes the π-acceptor properties of the phosphine moiety. The η(5)-coordination was achieved when pyrrolides 4-K and 5-K were reacted with [Mn(CO)5Br] to give 4-Mn(CO)3 and 5-Mn(CO)3, respectively. The energy of the HOMOs in these three legged-piano stool complexes decreases on PPh2-substitution (5-Mn(CO)3) stabilizing the Mn-CO bonds, whereas the inverse effect is noticed for P(iPr)2-substitution (4-Mn(CO)3).