The hydroboration of polyfunctional olefins with Et2BH prepared from commercially available Et3B and BH3·SMe2, followed by a treatment with neat Et2Zn (2 equiv) produces a range of new polyfunctional diorganozincs, some of which cannot be prepared by known methods. After transmetalation with CuCN·2 LiCl and addition of an electrophile (acid chloride, enone, nitro olefin, ethyl propiolate or allylic bromide), various polyfunctional products are obtained in 60-83 % overall yield (based on the olefin). The zinc reagents prepared in this way can also be used for the catalytic enantioselective addition to aldehydes (90-95 % ee).