[77197-59-2] · C7H16O4 · 1,1,1,3-Tetramethoxypropane · (MW 164.23)
(furnishes methyl a-substituted acrylates from allylic alcohols via Claisen orthoester rearrangement and b-elimination1-5)
Physical Data: bp 89-90 °C/20 mmHg.1
Solubility: CCl4, organic solvents.
Handling, Storage, and Precautions: keep away from moisture; use in a fume hood.
1,1,1,3-Tetramethoxypropane (1) is prepared1 from b-methoxypropionitrile6 by the Pinner reaction.7 It has been used as a synthon for the preparation of methyl a-substituted acrylates via Claisen orthoester rearrangement8 with allylic alcohols followed by b-elimination of methanol with base. Claisen orthoester rearrangement of allylic alcohols (2)-(4) with excess (1) and a catalytic amount of 2,4,6-trimethylbenzoic acid gave the esters (5)-(7).1 Treatment of these esters with one equivalent of Potassium t-Butoxide in THF (0 °C, 10 min) gave the a-substituted acrylates (8)-(10).1
The conversion of (11) to (12) and then (13) using this methodology has been reported.5
Another report describes the Claisen rearrangement of (14)1 and (15).2,3 These rearrangements, requiring a larger amount of acid catalyst and longer reaction times, provide the a-substituted acrylates (16) and (17) directly.
University of Washington, Seattle, WA, USA