Selective Reduction of Disulfides to Thiols with Potassium Triisopropoxyborohydride

Thirty Six Years of Research on the Selective Reduction and Hydroboration

“…The remarkable difference in the rate of aromatic and aliphatic disulfides suggested the possibility of establishing the practicality of a procedure under preparative conditions for the selective reduction of aromatic disulfides in the presence of an aliphatic disulfide. Indeed, we achieved to 99% reduction diphenyl disulfide, with only minor reduction of di-n-butyl disulfide 29 (Eq. 22).…”

“…[129][130][131][132][133] Furthermore, hydroxy-, alkoxy-, acetoxyand methanesulfonyl-incorporated diisopinocampheylborane derivatives (28)(29)(30)(31)(32)(33) were prepared and their applicability in MPV type reduction was explored.…”

“…As mentioned earlier, diisobutylaluminum derivatives (17)(18)(19)(20)(21)(22)(23) 114, 122,124,125,126,140,[144][145][146][147][148] and diisopinocampheylboron derivatives (25)(26)(27)(28)(29)(30)(31)(32)(33) 132, [135][136][137]140,[149][150][151][152][153] have been applied to the regioselective reduction of α,β-unsaturated aldehydes and ketones. All the derivatives examined can reduce a variety of α,β-unsaturated aldehydes and ketones to the corresponding allylic alcohols, except Ipc 2 BOR 135-138, which can only reduce aldehydes but not attack ketones at all.…”

Synthesis of End-Functionalized Star-Shaped Poly(methylthiirane)s

“…A lot of methods are described in the organic chemistry involving various reactants: complex hydrides (NaBH 4 , [20] AlLiH 4 , [21] KBH(O-iso-C 3 H 7 ) 3 , [22] AlLiH(O-tert-Bu) 3 [23] ), dithiols for equilibrated exchange: dithiothreitol and propanedithiol, [24] and classical reducing agents such as hydrazines, [25] triphenylphosphine/H 2 O, [26] zinc/acetic acid. [27] Most of these reactants are not suitable for use in macro- molecular chemistry often because of their poor solubility in polymer solvents.…”

“…This slight degradation could perhaps be avoided by using milder but non commercially available reducing agents such as KBH(O-iso-C 3 H 7 ) 3 . [22] Unfortunately, the hydride method is not suitable for tetra-armed polymers synthesized from PETMP; even with very selective mild reducing agent such as KBH(OC 3 H 7 ) 3 or AlLiH(iso-Bu) 3 , which could preserve the ester functions, the hydrolysis in acidic medium can lead to break the ester functions.…”