Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris
Catalytic Access to Bridged Sila-<i>N</i>-heterocycles from Piperidines via Cascade sp<sup>3</sup> and sp<sup>2</sup> C–Si Bond Formation
作者:Jianbo Zhang、Sehoon Park、Sukbok Chang
DOI:10.1021/jacs.8b08733
日期:2018.10.17
Described herein is the development of an unprecedented route to bridged sila- N-heterocycles via B(C6F5)3-catalyzed cascade silylation of N-aryl piperidines with hydrosilanes. Mechanistic studies indicated that an outer-sphere ionic path is operative to involve three sequential catalytic steps having N-silyl piperidinium borohydride as a resting species: (i) dehydrogenation of the piperidine ring
[reaction: see text] The diastereoselective cyclization of bissulfonyl esters was investigated by varying both the size and the placement of the substituent on the tether adjoining the reacting centers. Substitution at either the alpha or beta position relative to the ester moiety gave diastereomeric ratios of (1-3):1, while gamma substitution dramatically increased the diastereomeric ratios to (6-20):1