Vanadium-Catalyzed Oxidation of tert-Butyl N-Hydroxycarbamate to tert-Butyl Nitrosoformate and Its Diels–Alder Reaction with Simple and Functionalized Dienes

Abstract

A general and efficient vanadium-catalyzed oxidation of tert-butyl N-hydroxycarbamate to tert-butyl nitrosoformate using alkyl hydroperoxides as terminal oxidants has been developed. The intermediate nitroso compound was trapped by in situ Diels-Alder reaction with simple and functionalized dienes, providing general access to a variety of functionalized 3,6-dihydro-2H-1,2-oxazines.

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

“…Recently, a vanadium-catalyzed nitroso hetero-Diels–Alder reaction between hexa-2,4-dien-1-ol ( 69 ) and Boc-protected hydroxylamine 68 was reported by Hoshino [96] (Scheme 18). This reaction, with the hydroxylamine oxidized in situ to the nitroso dienophile in the presence of vanadium in different solvents (CH 2 Cl 2 or toluene) and at different temperatures (−20 °C or rt), gave the hetero-Diels–Alder products 70 , 71 , with the ratio of 70 and 71 varying from 71:29–83:17, and yields between 65 and 99%.…”

Vanadium, niobium and tantalum

“…62 [VO(O i Pr) 3 ] was used to catalyse the cyanative self-condensation of aromatic aldehydes 63 as well as the oxidation of tert-butyl N-hydroxycarbamate to tert-butyl nitrosoformate. 64 The mechanism of the vanadium-catalysed Meyer-Schuster rearrangement with aldehydes and imines was examined computationally. 65 The oxoperoxovanadium complex [VO(O 2 )(PAH)(phen)] (PAHH = 2-phenylacetohydroxamic acid) was found to be an active catalyst for the peroxidative bromination of unsaturated alcohols in the presence of H 2 O 2 and KBr.…”

Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

“…These methodologies generally involve in situ generation of the acylnitroso species, achieved using a variety of oxidants including vanadium- [ 28 ], manganese- [ 19 – 21 ], iron- [ 23 – 24 ], copper- [ 22 , 31 ], rhenium- [ 26 ], and rhodium- [ 27 ] based reagents.…”