21776-94-3Relevant academic research and scientific papers
Synthesis of 2 h-chromenes via hydrazine-catalyzed ring-closing carbonyl-olefin metathesis
Jermaks, Janis,Lambert, Tristan H.,Macmillan, Samantha N.,Zhang, Yunfei
, p. 9259 - 9264 (2019/10/08)
The catalytic ring-closing carbonyl-olefin metathesis (RCCOM) of O-Allyl salicylaldehydes to form 2H-chromenes is described. The method utilizes a [2.2.1]-bicyclic hydrazine catalyst and operates via a [3 + 2]/retro-[3 + 2] metathesis manifold. The nature of the allyl substitution pattern was found to be crucial, with sterically demanding groups such as adamantylidene or diethylidene offering optimal outcomes. A survey of substrate scope is shown along with a discussion of mechanism supported by DFT calculations. Steric pressure arising from syn-pentane minimization of the diethylidene moiety is proposed to facilitate cycloreversion.
A New Route to o-Allenylphenols
Bhuvaneswari, N.,Venkatachalam, C. S.,Balasubramanian, K. K.
, p. 1177 - 1178 (2007/10/02)
Cathodic reduction of 3-bromochromenes led to a ring-opening reaction yielding o-allenylphenyl acetates.
Cobalt-mediated Radical Reactions in Organic Synthesis. Oxidative Cyclisations of Aryl and Alkyl Halides leading to Functionalised Reduced Heterocycles and Butyrolactones
Bhandal, Harcharan,Patel, Vinod F.,Pattenden, Gerald,Russell, Jamie J.
, p. 2691 - 2701 (2007/10/02)
Reactions between the CoI species derived from cobalt(III) salen (11) or cobalt(II) salophen (12) and (O-allyl) or (O-but-3-enyl) iodophenols lead to isolatable cobalt complexes, viz. (16) and (27), which can be converted into substituted benzofurans, i.e. (17) and (23), and benzopyrans, i.e. (28) and (34); similarly, interaction between compound (36) and Co1 salen led in one step to 1,3-dimethylindole (37).Radical cyclisation of the acetal (38a) in the presence of Co1 cobaloxime leads to the cis-ring-fused alkyl cobalt complex (42), which can be converted in a preparative manner into lactone (44) following 1,2-elimination and hydrolysis/oxidation, and into lactone (53) following insertion of molecular oxygen , reduction and hydrolysis/oxidation.
SYNTHESIS OF BENZOFURANS, INDOLES AND BENZOPYRANS VIA OXIDATIVE FREE RADICAL CYCLISATIONS USING COBALT SALEN COMPLEXES.
Patel, Vinod F.,Pattenden, Gerald,Russell, Jamie J.
, p. 2303 - 2306 (2007/10/02)
Reactions between the Co(I) species derived from cobalt(III) 'salen'(1), and (O-allyl) or (O-but-3-enyl)iodophenol, leads to isolatable cobalt complexes, viz (2), (13), which can be converted into substituted benzofurans, i.e. (5), (6) and benzopyrans, i.e. (14), (15); similarly interaction between (18) and Co(I) 'salen' led, in one step, to the 3-methylindole (19).
