Reduction triacetoxy borohydride

For the solution-phase preparation of functionalized tropanylidenes, the authors simply dispensed solutions of the bromo N-H precursor in 1,2-dichloroethane (DCE) into a set of microwave vials, added the aldehydes (3 equivalents) and a solution of sodium triacetoxy borohydride in dimethylformamide (2 equivalents), and subjected the mixtures to microwave irradiation for 6 min at 120 °C. Quenching the reductive amination with water and subsequent concentration allowed a microwave-assisted Suzuki reaction (Section 6.1.2) to be performed directly on the crude products [295]. 

The reduction can be carried out in a distereoselective manner also when the chiral group is in Imposition to the carbonyl. Moreover, a reversal of the sense of the diastereoselectivity can be achieved by the use of diisobutylaluminum hydride (dibal-H) or tetramethylammonium triacetoxy-borohydride (Me4NBH(OAc)3) to give 1,3-jyn or l,3-anti diols, respectively (Scheme 34) <93S903>. 

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