Palladium‐Catalyzed Enantioselective Oxidation of Chiral Secondary Alcohols: Access to Both Enantiomeric Series

Abstract

Rapid resolution: A new catalyst system for the oxidative kinetic resolution of secondary alcohols leads to dramatic rate increases. This system allows the use of a diamine to provide access to either enantiomer of a range of alcohols with good selectivity factors (see scheme). This method has been applied to the formal total synthesis of (−)‐amurensinine.

Recent advancements and challenges of palladiumII-catalyzed oxidation reactions with molecular oxygen as the sole oxidant

“…For example, O’Brien, Stoltz and co-workers recently reported the first example of a room temperature Pd II -catalyzed oxidative kinetic resolution of a variety of secondary alcohols using the Pd[(−)-sparteine]Br 2 catalyst with exogenous (−)-sparteine and Cs 2 CO 3 (Table 1, conditions A) 22. Both benzylic (11–13) and aliphatic ( 15 ) secondary alcohols can be resolved with k rel values comparable to the Pd[(−)-sparteine]Cl 2 catalyst at elevated temperatures 11,23.…”

Use of a palladium(II)-catalyzed oxidative kinetic resolution in synthetic efforts toward bielschowskysin

“…Furthermore, we have previously shown 2-aryl cyclic allylic alcohols to be exceptional substrates in our palladium(II)-catalyzed oxidative kinetic resolution. 9d Therefore, diastereoselective 1,2-reduction of the enone functionality in compound 12 provided the necessary substrate ( 15 ) with which to explore the palladium(II)-catalyzed oxidative kinetic resolution and allow us to establish the absolute stereochemistry at C(3).…”

“…We anticipated that the stereocenter in alcohol 8 would provide a basis for the application of a substrate-focused palladium(II)-catalyzed oxidative kinetic resolution, developed independently by the Sigman and Stoltz laboratories. 8,9 Accomplishing the latter would provide access to an enantioselective synthesis of cyclopropane 6 , as well as eventually bielschowskysin ( 1 ).…”

Oxidative Kinetic Resolution of Secondary Alcohols with Salen–Mn(III)/NBS/NaClO System

“…Among the many processes known, the oxidative kinetic resolution (OKR) of racemic secondary alcohols is a particularly attractive and efficient method [12][13][14][15]. Several chiral complexes pre-prepared or generated in situ from the corresponding chiral ligands with Pd [16][17][18][19][20][21][22], Ru [23][24][25], Ir [26][27][28], Co [29], Fe [30], and Mn [31][32][33][34][35][36][37][38][39] ions have been used as catalysts for the OKR of racemic secondary alcohols. Among these metal complexes, chiral Mn(III)-salen complexes [31][32][33][34][35][36][37] are of special interest due to their easy synthesis, mild reaction conditions and very short reaction time.…”