The Photolysis of Organic Nitrites. Ii. Synthesis of Steroidal Hydroxamic Acids

Radical‐Promoted C−C Bond Cleavage: A Deconstructive Approach for Selective Functionalization

“…[11] Themechanism relies on photolytic homolysis of nitrite into nitric oxide and an alkoxy radical (A), which undergoes b-fragmentation (Scheme 3). [12] Thef ormed tertiary alkyl radical B then captures the nitric oxide to furnish the nitroso aldehyde C, which leads to hydroxamic acid after cyclization.…”

β-Scission of Alkoxy Radicals in Synthetic Transformations

“…Barton and his co-workers reported a ring-opening functionalization of the D ring of steroidal alcohol 1 via a nitrite ester intermediate (Scheme 2). 10 The steroidal alcohol 1 is initially treated with nitrosyl chloride to introduce a nitrite group on the D ring. Photoirradiation induces homolysis of the NO bond of the nitrite 2 to generate the alkoxy radical 3 and a nitrosyl radical.…”

Photochemistry of hydroxamic acids and derivatives

“…Photooxidation of NKronos Bluhm and Weinstein observed84 that photoirradiation of a-phenylnitrones in nonpolar deaerated solvents produced long-lived radicals, identified as acyl aminoxyl radicals. lV-p-Tolyl-2-naphthalenehydroxamic acid (24) was detected among the products of the photoirradiation of a-(2-naphthyl)-N-p-tolylnitrone (M)35 (Scheme 6). The fact that the hydroxamic acid was found in deaerated solutions suggested that oxygen is liberated or transferred from nitrones under photoirradiation.…”

“…46 The results of photochemical investigations have confirmed this hypothesis. 66 In the case of the compounds containing Naryl substituents, for instance iV-p-tolyl-2-naphthalenehydroxamic acid (24), the fluorescence quantum yields are not high (<t>{ ~10-4), the difference between the </>f values of hydroxamic acids and their photoproducts (and/or intermediates) is not large, and the observed changes in fluorescence intensity are not spectacular. 46 lV-Methyl-2-naphthalenehydroxamic acid (33) exhibited the most extreme fluctuation behavior among the compounds studied.…”