Irradiation medium/high-pressure mercury arcs

A mixture of 250 mg 3,3-dimethyl-1,5,5-triphenyl-2-aza-l,4-pentadiene (0.80 mmol), 550 mg m-methoxyacetophenone (3.7 mmol) and 450 mL dry -BuOH was put into a quartz immersion well apparatus with a Pyrex filter. The solution was purged with argon for 1 h and was irradiated with a 400-W medium-pressure mercury arc lamp for 6 h. After completion of the irradiation, the solvent and the sensitizer were removed under reduced pressure, the residue was chromatographed with hexane/Et20 (99 1) as an eluent to afford 65.0 mg benzaldehyde, and 13.0 mg of cyclopropylimine as a colorless oil, in a yield of 5%. Further elution with Et20 yielded 25 mg of a highly polar material. Final elution with EtOH afforded 148 mg l,l-dimethyl-3,3-diphenyl-2-propenylamine, in a yield of 81%. 

C-H borylation of alkanes was first demonstrated by Hartwig using photochemical activation of Cp RefCOjj (Scheme 2.3) [51]. With irradiation from a 450 W medium-pressure Hanovia mercury arc lamp, alkylboronates are obtained by direct borylation of alkanes with pin2B2 in the presence of Cp Re(CO)j (2.4-5.0 mol%) and CO (2 atm). Pinacolborane is not effective for the borylation thus, one of two boron atoms participated in the catalytic cyde. All reactions resulted in high regiospecifidty for the functionalization of terminal primary carbons. 

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