Vitamin sidechain

To further probe the potential synthetic utility of the Zr-catalyzed enantioselective carboalumination of alkenes, the C14 sidechain units of vitamin E, that is, (2R,6R)-2.6.10-trimethyl-1 -undecanol (4) and the corresponding iodide 5, have been synthesized as summarized in Scheme 4.10 [15]. Whereas the enantioselectivity in each methylalumination step must be significantly improved, the four-step synthesis of 4 and 5 summarized in Scheme 4.10 appears to provide one of the most efficient enantioselective routes to the C14 sidechain units of vitamin E [16]. 

I. 4-naphthoquinone without a sidechain in the 3-position cannot exert all the functions of the K vitamins Isler, Wiss, Vi tarn. Norm. (New York) 17, 55 (1959),... 

---