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.
20.5.1.7.13.3 Method 3: Transesterification with Enzymes

DOI: 10.1055/sos-SD-020-00774

Zhang, M.; Hanson, P. R.Science of Synthesis, (200720932.

Transesterification is one of the reactions for which enzymes are utilized most effectively and this technology has experienced explosive expansion since about 1990.[‌339‌] Most of the enzymes involved in this technology are lipases, an indication of the pivotal position of these enzymes. Takabe and co-workers reported a highly regioselective transformation of various acyclic α,ω-terpenediols to monoacetates, e.g. 254, by lipase-catalyzed transesterification (Scheme 88).[‌367‌] Short-chain citronellyl esters, e.g. 255, are synthesized by transesterification reactions catalyzed by a new microbial lipase from a Rhizopus sp. strain, isolated in a solvent-free system or with hexane in the reaction medium; yields are up to 60% after 48hours (Scheme 88).[‌368‌] These results suggest that the size of the aliphatic chain from the acyl donor is important for the conversion rate. There is a unique regioselectivity between primary alcohols too (Scheme 88).[‌369‌] The 4-hydroxy group of diol 256 undergoes exclusive transesterification by isopropyl acetate with the aid of Candida cylindracea lipase to give 4-hydroxybutyl acetate 257 (Scheme 88).

Meeeee 88 Meeeee-Meeeeeeee Meeeeeeeeeeeeeeeeeee[‌888‌‌888‌]

Meeeeeeeeeeeeeeeeee eeeeeeeee ee eeeeeeeeeee eeeeee ee eeee eeeeeeee. Meee, eeeee eee­eeeeee eee ee eeeeeeeeeee ee eeeeeeeeeeeeeeeeeee ee eeeee eeeeeee eeee eeeeeeee eeee ee eeeeee ee ee eeeeeeeeeee eeeeee eeee e Meeeeeeee eeeeee ee. ee eeee (Meeeee 88).[‌888‌] Mee eeeeeee eeeee eeeeeeeee (88%) ee eeeee eeee eee eeeeeeeee eeeeeeeeeeeee ee 8.8M (8:8), eee eeeeee eeeeeeeeeeeee ee 88e·M8, eee eeeeeeeeeee ee 88°M eee eee eeeeeeeeee eeee ee 88eeeee. Meeeeeeeeeeeeeeeeee ee eeeeeee eeee eeeee eeeeeee ee eeeeeeee ee 88°M eeee Meeeeeeeeee ee. eeeeee eeeeeeeeeee ee eeeeeeeee ee eeeeeeee ee eee eeeeeeee (Meeeee 88).[‌888‌]

Meeeee 88 Meeeeeeeeee-Meeeee-Meeeeeeee Meeeeeeeeeeeeeeeeeee[‌888‌,‌888‌]

Me ee eeeeee ee eeee eeee eeeeee-eeeeeeeee eeeeeeeeeeeeeeeeeee ee eeeee eeeeeee eeeeeeee eeee eeeeeeee eeeeeeeeeeeeeeeeee: e eeeeee eeee ee Meeeeee eeeeeeeeee eeeeee M (MMMM) eee Meeeeeeeeee eeeeeee eeeeee eee ee ee 88 eeeee eeee eeeeeeeeeeeeeeee ee eeeee eeeeeee eeee ee eeeeeeeeeeee eeeeeee eeeeeeee.[‌888‌]

Meeeeeeeeeee Meeeeeeee

Meeeeeeeeee Meeeeee (888); Meeeeee Meeeeeeee:[‌888‌]

Mee eeeeeeeee eee eeeeeee eee ee eeeee-eeeeee eeeee eeeeeeeeee ee eeeeeeeee eeeee ee eeeeeeeeeee eeeeeee eee eeeeeee (M8=Me, Me), eeeeeeeee eeeeee (8% e/e eeeeeeeee), eee 88 eeeeee eeeee. Mee eeeeeeeeeee eeee eeeeeeeee eeee eee eeeeeee eeeeee. Meeeeee ee 88 µM eeee eeeeeeeee eeeee 8, 8, 8, 88, 88, 88, eee 88e ee eeeeeeee eeee eee eeeeeeee ee MM.

References