Synthesis of dichloroindium hydride and exploration of its reactivity with organic functional groups. Tandem, selective and partial reductions of halo-nitriles

Abstract

Dedicated to Professor Keith Smith on the occasion of his 65th anniversary AbstractMethods for the in situ generation of dichloroindium hydride (HInCl 2 ) via the reduction of InCl 3 with various reducing agents, such as tributyltin hydride (tributylstannane; Bu 3 SnH), diisobutylaluminum hydride (DIBAL-H), triethylsilane (Et 3 SiH), lithium aminoborohydride (LAB), and sodium borohydride (NaBH 4 ), in various solvents are reviewed and compared. The use of the InCl 3 /NaBH 4 system in addition to forming HInCl 2 , also generated borane that was trapped as BH 3 -tetrahydrofuran (THF). Carefully controlling the activity of these reducing agents allows for the selective and/or partial reduction of multi-functionalized compounds containing nitriles and halogens.

Stereocontrolled Synthesis of a Possible Stereoisomer of Laurenidificin and a Formal Total Synthesis of (+)-Aplysiallene Featuring a Stereospecific Ring Contraction

“…Next, our attention was focused on the synthesis of the Z -enyne side chain by employing hydroindation chemistry. , To introduce the requisite alkyne terminal, propargylation of 13 was carried out with propargyl bromide and zinc dust using 1,2-dibromoethane as the activator of zinc . Remarkably, the 6 R- configured alcohol 6 was exclusively produced in 67% yield.…”

Binary reducing agents containing dichloroindium hydride for the selective, partial, or tandem reductions of bifunctional compounds consisting of halo-nitriles, halo-esters and halo-carboxylic acids

“…Additionally, we had previously explored the preparation of HInCl 2 from InCl 3 and lithium aminoborohydride (LAB) but this system required a careful control of the stoichiometry of the reactants (eqn (3)). [10][11][12][13] Baba and Oshima have shown that HInCl 2 can also be generated from InCl 3 and diisobutylaluminum hydride (DIBAL-H) at 0 °C (eqn (4)). [14][15][16] Oshima and coworkers have demonstrated that HInCl 2 and catalytic amounts of Et 3 B selectively reduced alkyl halides in the presence of aromatic esters and aromatic ketones.…”