Indan benzylic hydroxylation

The enantioselective benzylic hydroxylation of indan and tetralin can be achieved with M. isabellina, affording 78 % conversion to 1-indanol (64 % yield, 86 % (11 )- ee) in a 2-day incubation and 52 % conversion to 1-tetralol (38 % yield, 92 % (11 )- ee) in a 4-day incubation. The good yields and ee allow their use in future scahng-up processes however, to avoid the lack of efficiency, careful control of the temperature, pH and medium is necessary, since the reactions are strongly dependent on the incubation and reaction conditions. Tables 12.2 and 12.3 give details of some of the different incubation condi-tions/results and time-course analysis found in the benzyhc hydroxylation of indan and tetrahn mediated by M. isabellina CCT3498. 

Table 12.2 Benzylic hydroxylation of indan and tetralin mediated by M. isabellina...

Table 12.3 Time-course analysis obtained in the benzylic hydroxylation of indan and tetralin (30 mg) byM. isabellina (3 g fresh weight) ...

Microorganisms degrading indane derivatives were screened for stereoselective oxidation of racemic cis- or trans-1,2-indandiol. Three promising strains specifically oxidizing the benzylic hydroxyl group were found (see Table 16.2-15). 

Z. (2009) Enantioselective benzylic hydroxylation of indan and tetralin with Pseudomonas monteilii TA-5. Tetrahedron Asymmetry, 20 (10), 1206-1211. 

Figure 23 Benzylic hydroxylations of indan and indene by P. putida.

Figure 24 Benzylic hydroxylations of 2-substituted indans by P. putida.

Enantioselective Benzylic Microbial Hydroxylation of Indan and Tetralin... 

The tra x-[Ru (0)2(por)] complexes are active stoichiometric oxidants of alkenes and alkylaro-matics under ambient conditions. Unlike cationic macrocyclic dioxoruthenium I) complexes that give substantial C=C bond cleavage products, the oxidation of alkenes by [Ru (0)2(por)] affords epoxides in good yields.Stereoretentive epoxidation of trans- and cw-stilbenes by [Ru (0)2(L)1 (L = TPP and sterically bulky porphyrins) has been observed, whereas the reaction between [Ru (0)2(OEP)] and cix-stilbene gives a mixture of cis- and trani-stilbene oxides. Adamantane and methylcyclohexane are hydroxylated at the tertiary C—H positions. Using [Ru (0)2(i)4-por)], enantioselective epoxidation of alkenes can be achieved with ee up to 77%. In the oxidation of aromatic hydrocarbons such as ethylbenzenes, 2-ethylnaphthalene, indane, and tetrahydronaphthalene by [Ru (0)2(Z>4-por )], enantioselective hydroxylation of benzylic C—H bonds occurs resulting in enantioenriched alcohols with ee up to 76%. ... 

---