Pau Bayón

Diastereoselective synthesis of allosecurinine and viroallosecurinine from menisdaurilide.

A new and versatile synthetic route to Securinega alkaloids is reported. The first synthesis of allosecurinine has been accomplished in seven steps and 40% yield, starting from (+)-menisdaurilide, using a vinylogous Mannich reaction as the key transformation. Similarly, viroallosecurinine has been synthesized from (-)-menisdaurilide.

Use of chiral B(III) complexes in the cycloaddition of C,N-diphenylnitrone to tert-butyl vinyl ether

Abstract The 1,3-dipolar cycloaddition of C , N -diphenylnitrone to tert -butyl vinyl ether in the presence of several chiral Ti(IV) species which incorporate different bidentate C 2 -symmetrical ligands has been investigated. Several complexes have shown very efficient catalytic activity. The endo / exo selectivity of the process can be dramatically reversed in relation to the uncatalysed reaction, but low enantioselectivities up to 41% ee are found.

Iterative Synthetic Strategy for Azaphenalene Alkaloids. Total Synthesis of (−)-9aepi-Hippocasine

A new strategy for the stereoselective synthesis of alkaloids with perhydro-9b-azaphenalene skeleton has been developed. The starting material is the substituted glutarimide derivative 1, readily available in either enantiomeric form through the palladium-catalyzed asymmetric allylic alkylation of glutarimide. The strategy relies on an iterative methodology encompassing two nucleophilic allylations and two ring closing metathesis processes. The approach has been used in the first synthesis of (-)-9a- epi-hippocasine.