Regiocontrolled Wacker Oxidation of Cinnamyl Azides

Abstract

A highly regioselective Wacker oxidation has been developed for the oxidation of cinnamyl azides. The catalytic oxidation tolerates the azide functionality, and more than 15 β-azido ketones were isolated (25-92% yield). High regioselectivity for the aryl ketone is observed in all cases. A robustness screen was conducted to determine functional group tolerance. The products of the oxidaiton can be readily diversified.

Dative Directing Group Effects in Ti-Catalyzed [2+2+1] Pyrrole Synthesis: Chemo- and Regioselective Alkyne Heterocoupling

“…This reaction represents the first example of Ti-catalyzed directed alkyne hydroamination, and it yields electronically unbiased dissymmetric ketones that are difficult to synthesize selectively via Wacker oxidation of internal alkenes. 49–54 It is notable that weakly Lewis-basic dialkyl ether of 1z is capable of directing selective alkyne [2+2] cycloaddition despite stoichiometric quantities of aniline.…”

Allylic azides: synthesis, reactivity, and the Winstein rearrangement

“…[221][222][223] Topczewski and co-workers recognized that the electron withdrawing property of allylic azides could induce selectivity in the Wacker oxidation of cinnamyl azides (Scheme 41). 50 In this case, selective oxidation was attained at the benzylic position. Comparing the selectivity to the Wacker oxidation of β-methyl styrene indicates that the azide plays a critical role in the observed selectivity.…”

“…The most well-established method to access allylic azides is through nucleophilic substitution with sodium azide (Schemes 1a and 2a). [49][50][51][52][53][54][55] Allylic systems are typically activated for substitution and a wide range of electrophiles undergo substitution with azide anion including halogens, sulfonates, and some activated esters (Scheme 2a). As expected for a nucleophilic substitution, this reaction typically occurs with inversion of configuration.…”

On the Winstein rearrangement: equilibrium and mechanism

“…There have been reports utilizing the single conjugated isomer synthetically. 10,11 Scheme 5. Effects of conjugation to arene on equilibrium.…”