Catalytic enantioselective dehydrogenative Si–O coupling of oxime ether-functionalized alcohols

Add time:08/13/2019    Source:sciencedirect.com

Asymmetric silylation of alcohols is an unusual but effective approach to their kinetic resolution, and the Cu–H-catalyzed dehydrogenative Si–O coupling is particularly noteworthy as dihydrogen is formed as the sole by-product. Our laboratory had previously reported on diastereoselective (with silicon-stereogenic silanes) and enantioselective (with achiral silanes) Si–O couplings of azine donor-functionalized alcohols. The limitation, that is, the requirement of a nitrogen donor atom, prompted us to seek equally useful donor groups. Oxime ethers were identified as a suitable alternative, and we describe herein the preparation of a series of oxime ether-functionalized alcohols. To assess different substitution patterns in their kinetic resolution, these were tested in the reagent-controlled Si–O coupling using a silicon-stereogenic silane. The optimal substituents at the oxime carbon atom (dr=85:15 in the diastereoselective coupling) were then chosen for the related catalyst-controlled Si–O coupling but selectivity factors were only moderate.

We also recommend Trading Suppliers and Manufacturers of 4-METHYL-2-PENTANONE OXIME (cas 105-44-2). Pls Click Website Link as below: cas 105-44-2 suppliers

Prev:Direct activation of GABAA receptors by substances in the organic acid fraction of Japanese sake
Next:Characterization of membranes based on cellulose acetate butyrate/poly(caprolactone)triol/doxycycline and their potential for guided bone regeneration application)