Investigations into the preparation of sila-β-diketones via 2-trimethylsilyl-1,3-dithianes: structural characterization of a second polymorph of bis(2,2,6,6-tetramethyl-2-sila-3,5-heptanedionato)copper(II)

Pot-Economy Autooxidative Condensation of 2-Aryl-2-lithio-1,3-dithianes

The autoxidative condensation of 2-aryl-2-lithio-1,3-dithianes is here reported. Treatment of 2-aryl-1,3-dithianes with n-BuLi in the absence of any electrophile leads to condensation of three molecules of 1,3-dithianes and formation of highly functionalized α-thioether ketones orthothioesters in 51-89% yields upon air exposure. The method was further expanded to benzaldehyde dithioacetals, affording corresponding orthothioesters and α-thioether ketones in 48-97% yields. The experimental results combined with density functional theory studies support a mechanism triggered by the autoxidation of 2-aryl-2-lithio-1,3-dithianes to yield a highly reactive thioester that undergoes condensation with two other molecules of 2-aryl-2-lithio-1,3-dithiane.

Synthesis of diverse acyclic precursors to pyrroles for studies of prebiotic routes to tetrapyrrole macrocycles

Some 50 ketones, β-diketones, β-ketoesters and α-aminoketones have been prepared for studies of the formation of trisubstituted pyrroles equipped for self-condensation leading to tetrapyrrole macrocycles.