A Scalable Synthesis of (<i>R</i>)-3,5-Dihydro-4<i>H</i>-dinaphth[2,1-<i>c</i>:1‘2‘-<i>e</i>]azepine
作者:Masaya Ikunaka、Keiji Maruoka、Yoshiaki Okuda、Takashi Ooi
DOI:10.1021/op034067t
日期:2003.9.1
Environmentally benign scalable procedures are developed to supply enantiomerically pure (R)-3,5-dihydro-4H-dinaphth[2,1-c:1'2'-e]azepine 1 as its hydrogen oxalate salt in a five-step overall yield of 41%, which consist of the following: (1) his O-triflation of (R)-1,1'-bi-2-naphthol 8 [(CF3SO2)(2)O, pyridine, PhMe; quantitative yield]; (2) Kumada's cross-coupling [MeMgI, NiCl2(dppp), tent-BuOMe; 96% yield]; (3) radical bromination [N-bromosuccinimide, 2,2'-azobisisobutyronitrile, cyclohexane; 54% yield]; (4) cyclization [allylamine, Et3N, THF, 86%]; (5) N-deallylation [1,3-dimethylbarbituric acid, Pd(OAc)(2), Ph3P, PhMe] followed by crystalline salt formation with oxalic acid (overall 92% yield).