Preparation of Highly Reactive Electrogenerated Zinc

Logam zink berkereaktifan tinggi yang dihasilkan secara elektrolisis (EGZn/Naph) disediakan dengan mudah dalam larutan N,N–dimetilformamida (DMF) yang mengandungi naftalena dan elektrolit penyokong di dalam sebuah sel yang telah dipasang siap dengan katod platinum dan anod zink. EGZn/Naph ini adalah agregat zarah sangat halus yang lebih kecil berbanding logam zink komersial ataupun zink yang dihasilkan secara elektrolisis biasa (EGZn). Kereaktifan zink berkereaktifan tinggi ini dibuktikan dengan transformasi bromoalkana kepada organozink bromida yang berkesan, yang tidak boleh dicapai dengan menggunakan zink biasa mahupun logam EGZn. Reaksi ganding silang organozink bromida ini dengan iodobenzena mudah berlaku dalam kehadiran mangkin paladium untuk menghasilkan produk terganding silang, etil 4–fenilbutanoata sebanyak 96%. Kata kunci: Elektrolisis, reaktif zink, naftalena, bromoalkana, organozink kompoun Highly reactive electrogenerated zinc metal (EGZn/Naph) was readily prepared by the electrolysis of an N,N–dimethylformamide (DMF) solution containing naphthalene and a supporting electrolyte in a one–compartment cell fitted with a platinum cathode and a zinc anode. This EGZn/Naph is an aggregation of very fine particles which are much smaller in size than commercial zinc metal or the usual electrogenerated zinc (EGZn). The reactivity of this highly reactive zinc was elucidated by the efficient transformation of bromoalkane into the corresponding organozinc bromide, which cannot be achieved by the use of both usual zinc or EGZn metals. Subsequent cross–coupling reaction of the organozinc bromide with iodobenzene readily took place in the presence of a palladium catalyst to give the corresponding cross–coupled product, ethyl 4–phenylbutanoate in 96% yield. Key words: Electrolysis, reactive zinc, naphthalene, bromoalkanes, organozinc compound.

The preparation and characterization of 2-propylphosphinediacetic acid

Phosphineacetic acids of the RP(CH2COOH)2 type, where R is a large substituent with a +I-effect, cannot be prepared by the reaction of chlorophosphine with an organozinc compound because of the lability of the P-CH2COO bonds. The bis(ethyl ester) of 2-propylphosphinediacetic acid as the simplest substance of this kind was prepared by the reaction of chlorophosphine with ethylacetate enolate, which is universal for these substituents. 2-Propylphosphinediacetic acid, obtained from the ester by the usual procedure, was characterized with respect to its use as a hydrophilic phosphine ligand.