Navigation

0 Hits

  • Previous / Next

You are using Science Of Synthesis as a Guest.
Please login or sign up for a free trial to access the full content.
3.19.2.2 Asymmetric Acylation of Secondary Amines

DOI: 10.1055/sos-SD-203-00526

Oriyama, T.Science of Synthesis: Stereoselective Synthesis, (20113846.

The kinetic resolution of 2-substituted indolines catalyzed by a planar-chiral catalyst derived from 4-(pyrrolidin-1-yl)pyridine proceeds smoothly to afford the corresponding chiral indolines bearing a stereocenter at the 2-position (9098% ee).[‌70‌] Enantioselective N-acylation of secondary amides using enzymes or synthetic catalysts has never been reported. However, the kinetic resolution of various racemic oxazolidin-2-ones using catalyst (+)-31 proceeds smoothly at room temperature to afford the corresponding enantiomerically enriched secondary amides 50 and tertiary amides 51 (Scheme 22).[‌71‌] Investigation into the effects of substrate structure reveals that replacement of the phenyl group (Ar1=Ph) with a 1-naphthyl group leads to increased enantioselectivity. Asymmetric acylation of geminal dimethyl substrates (R1=Me) proceeds more slowly than for unsubstituted substrates. In these cases, higher conversions are obtained on a convenient time scale by doubling the catalyst and anhydride loadings.

Meeeee 88 Meeeeee Meeeeeeeee ee Meeeeeeee Meeeee[‌88‌]

Meeeeeeeeee 88

Me8 M8 Meee (e) Meeeeeeeeeee,e (e) eee (%) Meeeeeeeee (%) Mee
Me M 8.8 888 88.8 88 [‌88‌]
8-eeeeeeee M 88 888 88.8 88 [‌88‌]
8-eeeeeeee M 88 888 88.8 88 [‌88‌]
8-eeeee M 8.8 88 88.8 88 [‌88‌]
8-eeeeeee M 8 888 88.8 88 [‌88‌]
Me Me 88 888 88.8 88e [‌88‌]
8-eeeeeeee Me 8 888 88.8 88e [‌88‌]
8-eeeeeeee Me 8.8 888 88.8 88e [‌88‌]

e Meeeee eeeeeeeeee eee eeeeeee 88.

e Mee eeeeeeeeeee eeeeeee (e) eee eeeeeeee ee eee eeee.

e 8eee% ee (+)-88 eee eeee.

Meeeeeeeeeee Meeeeeeee

(M)-8-Meeeeeeeeeeeee-8-eeee 88 eee (M)-8-Meee-8-(8-eeeeeeeeeeeeeee)eeeeeeeeee-8-eeee 88; Meeeeee Meeeeeeee:[‌88‌]

M eeeee eeee eee eeeeeeee ee eeeeeeeeee eeeeeeee (+)-88 (88ee, 8.888eeee) eee eMe8MMe (8.88eM, 8.88eeee) ee MMMe8 ee e 88.8-eM eeeeeeeeee eeeee, eee eeeeeeee eee eeeeee ee ee eee eeee. Mee 8-eeee eeeee eeee eeee eeeeeee eeee eee eeeeeee eeeeeeeeee-8-eee (8.88eeee) eee eee eeeee eeee (8.88eM). Meeee eee eeeeeeeee eee eeeeeeeee Me8MM8 (888ee) eee eeeee, eee eee eeeeeeeee eeeeeee eee eeeeeeeeeeee eeeeeee ee ee eeeeee eeeee eeeeeee eeee (eMeMM)8M (88.8µM, 8.888eeee). Meee eeeeeee eee eeeeeee ee ee eee eee eeeeeeee eee eeeeeeeee ee 8MMMM eee eeeeeeee ee eeeeeeee ee MeMM (8.8eM) eeee ee eeeeeee eeeeeeee eee eeeeeeee (eeee eeee 8% eeeeee ee eee eeeee ee eeeeeeeeee ee 8e). Mee eeeeeeeee eeee eee eeeeeeeeeeee eee eeeeeeeee ee eeeee eeeeeeeeeeeeee (MeMMe/eeeeeee 88:88). Mee eeeeeeeee eeeeeeeee eee eee M-eeeeeeee eeeeeeeeee eeee eeeeeeeee eeee eeeeeeee ee eeeeee eeeeeeeeee eeeee MMMM.

References