Efficient allylation of aldehydes with allyltributylstannane catalyzed by CuI

Tricyclic Fused Lactams by Mukaiyama Cyclisation of Phthalimides and Evaluation of their Biological Activity

We report that phthalimides may be cyclized using a Mukaiyama-type aldol coupling to give variously substituted fused lactam (1,2,3,9b-tetrahydro-5H-pyrrolo[2,1-a]isoindol-5-one) systems. This novel process shows a high level of regioselectivity for o-substituted phthalimides, dictated by steric and electronic factors, but not for m-substituted phthalimides. The initial aldol adduct is prone to elimination, giving 2,3-dihydro-5H-pyrrolo[2,1-a]isoindol-5-ones, and the initial cyclisation can be conducted in such a way that aldol cyclisation-elimination is achievable in a one-pot approach. The 2,3-dihydro-5H-pyrrolo[2,1-a]isoindol-5-ones possess cross conjugation and steric effects which significantly influence the reactivity of several functional groups, but conditions suitable for epoxidation, ester hydrolysis and amide formation, and reduction, which provide for ring manipulation, were identified. Many of the derived lactam systems, and especially the eliminated systems, show low solubility, which compromises biological activity, although in some cases, antibacterial and cytotoxic activity was found, and this new class of small molecule provides a useful skeleton for further elaboration and study.

Rapid synthesis of homoallylic alcohol from aldehyde with allyltributylstannane under solvent-free conditions

A catalytic amount (2 mol %) of phosphotungstic acid (PTA) is sufficient to synthesize homoallylic alcohol in excellent yields from aldehyde with allyltributylstannane upon grinding under solvent-free reaction conditions. Easy handling, very short reaction time, solvent-free reaction conditions, and aqueous workup free isolation protocol may make our method very useful for synthetic chemists.