Piperonyl bromide

The Lewis acid-catalyzed aza-Payne rearrangement was utilized in the total synthesis of ep/-7-deoxypancratistatin by T. Hudlicky and co-workers. The 2,3-aziridino alcohol was treated with f-BuLi, to generate the epoxy amide that was trapped with piperonyl bromide. 

In early 1997, de Oliveira and his group (89) reported an approach to the tetracyclic core of cephalotaxine that essentially mimicked the earlier chemistry reported by Danishefsky (33) (see Scheme 9, Section III). The thio amides 311 and 312 (Scheme 54) were prepared by alkylation of succinimide with the corresponding )3-piperonyl bromide prepared in two steps from safrole, then functionalized further to the nitrile or ester by chloromethylation, followed by displacement and/or hydrolysis and esterification. The base-catalyzed closure produced the tetracyclic ring systems 313 and 97 in 75 and 22% yield, respectively. These compounds were thus... 

The first micellar activation of a transition-metal catalyzed reaction was introduced by Menger et al., who proved the rate and yield enhancements of the oxidation of piperonal into piperonylic acid by KMn04 at 55 °C along with the in situ addition of 0.01 M of cetyltrimethylammo-nium bromide (CTAB). " Transition metal complexes were also extended toward dual catalytic systems in aqueous catalytic Pauson-Khand-type reaction. It was shown that... 

Recently, the two-phase permanganate oxidation of piperonal to piperonylic acid (Eq. 11.2) has been carried out. A 65% yield was obtained when cetyltrimethylammo-nium bromide was present in the reaction mixture [5]. 

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