Hydrosilanes Are Not Always Reducing Agents for Carbonyl Compounds, II: Ruthenium‐Catalyzed Deprotection of tert‐Butyl Groups in Carbamates, Carbonates, Esters, and Ethers

Abstract

Hydrosilanes act as a reagent to cleave the C–O bond of OtBu groups in carbamates, carbonates, esters, and ethers by catalysis of a triruthenium cluster. The reaction offers a novel deprotection method for OtBu groups under neutral conditions, showing unique selectivities that have never been accomplished with conventional Brønsted or Lewis acidic promoters. Possible mechanisms for C–O cleavage are discussed on the basis of NMR spectroscopic analysis.

Suzuki-Miyaura Reactions Catalyzed by C2-Symmetric Pd-Multi-Dentate N-Heterocyclic Carbene Complexes

“…13 C-NMR (101 MHz, CD 3 OD) δ 157.93, 142.18, 133.74, 129.60, 128.96, 127.30, 127.28, 116.53, 49.43, 49.21, 49.00, 48.79, 48.57 ppm. The NMR spectral data matched literature data [ 50 , 51 ]. MS (EI): m/z = 170 [M + ].…”

Homogeneous Catalysis by Organometallic Polynuclear Clusters

“…In another example, the presence of Me2S in mixtures of aldehydes and ketones selectively suppressed reduction of the ketones [125]. Furthermore, under neutral conditions 80 catalyzes the cleavage P. 27 of 52 of the C-O bond in a range of functionalities containing the C-O t Bu unit, including N-and O-Boc as well as t Bu-esters and t Bu-ethers [126]. Further substrate selectivity was demonstrated by varying the source of silane.…”

Development of a Triazine‐Based tert‐Butylating Reagent, TriAT‐tBu

“…tert ‐Butyl 3‐Phenylpropyl Ether (2b): 1 H NMR (CDCl 3 ): δ = 7.30–7.24 (m, 2 H), 7.23–7.14 (m, 3 H), 3.36 (t, J = 6.4 Hz, 2 H), 2.68 (t, J = 7.9 Hz, 2 H), 1.90–1.80 (m, 2 H), 1.19 (s, 9 H) ppm. 13 C NMR (CDCl 3 ): δ = 142.4, 128.6, 128.4, 125.8, 72.7, 60.9, 32.6, 32.3, 27.8 ppm.…”