0 Hits

  • Previous / Next

You are using Science Of Synthesis as a Guest.
Please login to access the full content or check if you have access via
37.2.3 Synthesis by Carbonyl Epoxidation

DOI: 10.1055/sos-SD-037-00188

Aggarwal, V. K.; Crimmin, M.; Riches, S.Science of Synthesis, (200837321.

General Introduction

Epoxides have found long-standing applications in organic synthesis due to their propensity to undergo highly regio- and stereoselective ring-opening reactions.[‌1‌,‌2‌] These strained three-membered heterocyclic ethers are typically aerobically and thermally stable compounds, which may be isolated by standard synthetic chemistry techniques. Exceptions to this, however, include particularly strained epoxides, or those that are functionalized by electron-donating substituents, which can render them unstable under acidic, basic, or thermal conditions.[‌3‌] 1,2-Disubstituted, 1,2,2-trisubstituted, and 1,1,2,2-tetrasubstituted epoxides may potentially exist as a mixture of trans- and cis-diastereomers due to the two contiguous stereocenters of the heterocyclic ring. Often the stereoisomers may be differentiated by chromatographic techniques and separated by preparative chromatography. Importantly for 1,2-disubstituted epoxides, the trans- and cis-diastereomers may be distinguished by 1H NMR spectroscopy, with 3J1H1H coupling constants taking typical values of approximately 3 and 4.5Hz for trans- and cis-epoxides, respectively.[‌4‌] Similarly, nuclear Overhauser effect (nOe) techniques may be used to differentiate the diastereomers of 1,2,2-trisubstituted and 1,1,2,2-tetrasubstituted epoxides.

Meeeeeee eeeeeeeeeee eee ee eeeeeeee ee eee eeeeeeee ee e eeeeeee ee eeeeeee eeeeeeeeee ee eee M=M eeee ee e eeeeeeee eeeee.[‌8‌] Meeee eeeee eeeeeee eeee eeee eeeeeeeee eee eee eeeeeeeee ee eeeeeeee ee eeee eeeeee: (8) eee eeeeeeee ee ee eeeee 8 ee e eeeeeeee eeeee, (8) eee eeeeeeee ee eeeeeeeee 8 eeeeeee ee eeeeeeee eeeeeee eeeee, eeeeeee ee α-eeee eeeeeeeee, ee e eeeeeeee eeeee, eee (8) eee eeeeeeee ee e eeeeeee 8 ee eeeeeeeeeeeeee 8 ee e eeeeeeee eeeee (Meeeee 8).

Meeeee 8 Meeeeee ee Meeeeeee Meeeeeeeeee

Me eeeee ee eeeeeee ee e eeeeeeeee eeee ee eeeeeeee eeeeeeeeee eeeeeee e eeeeee eeeeeeee eeeeee (eeeeeeee ee eee eeee ee eeeeeeeeeee eee eeeeeeee eeeeee, eee eeeeee eeee ee eeeeeeeeeee eeee, ee eeeeee eeee eeeee eeeeeeee ee Meeeeee ee Meeeeeeee, ee eee eeeeeeeee eeee eeeeee e eeeeee eeee eeeeeee eee eeeeeeeeee eee eeeeee). Meeeeeeee, ee α-eeee eeeeeeeee ee e eeeeeeeee eeee ee eeeeeeee eeeeeee eeeee. Meee eee ee eeeeeeeeee ee eeeeeeeeee eee eeeeeeee eee eeeeee ee eeeeeee, eee eeeeee ee eeeeeeeeee eeeeeee eee eeeeeeee e eeeee eeeeeeeeee. Meee eeeeeee eeeeeee eeeeeeeee eeee eeeeeeee eeeeeeeee eee e eeeeeeee eeeeeeeeeeeeeeeeeee eeeeeeeee (Meeeee 8). Mee eeeeeeeeeeee eeeeeeee ee ee eeeee ee e eeeeeeee eeeee e eeeeee-eeeeeee 8,8-eeeeeeeeeeee eeeeeeeeeeee, ee eeeeeee, eeee eee eeeeeee e eeeeeeeeee MM8 eeee eeeeeee ee eeeee ee eeeeeee (Meeeee 8, eeee e). Meeeeeeee, eee eeeeeeeeeeee eeeeeeee ee ee α-eeee eeeeeeeee ee e eeeeeeee eeeee e β-eeeeeeeeeeee eeee eee eeeeeee ee eeeeeeeee eeee-eeeeeee eeeeeeee (MM eeee MM eeee eeeeeeeee) (Meeeee 8, eeee e). Meee ee eeeee eeeeeeee ee ee eee Meeeeee eeeeeeee.

Meeeee 8 Meeeeeeeeee MeeeeeeeMeeeeeeeeee Meeeeeeee; MM eeee MM Meee Meeeeeeee

Mee eeeeeeeeeeeeeee ee eee α-eeee eeeeeeeee ee eee eeeee ee eeeeeeeee eeeeeeeeeeee ee eee eeeeeeeee eee, ee eeeeeee, α-eeee eeeeeeeeee eee eeee eeeeee, eee eeeee eeee eeeeeeeeeeee, eeee eee eeeeeeeee eeeeee. Meeeeeeeeee, eee eeeeeeeee ee eeeee 88 eee 88 eeeeee eeeeeeeee ee eee eeeee eeeeeeeeee > eeeeeee > eeeeeeee > eeeeeee > eeeeeeee; eeeeee > eeeeeeee > eeeeeeeee > eeeeee (Meeee 8).[‌8‌,‌8‌] Me eeeeeee, eeeeee eee ee eeeeeee eeee eeeee eeeeeeeeee: (8) eeeeeeeeeeeee eeeeee eeee eeeeeee ee eeeee eeeeeeeeeee eeeeee eee eee eeeee eeeeeeeeee (e.e., 8, M8=M8=M, eeeee), (8) eeeeeeeeeeeeee eeeeee eeee eeeeeee eeeeeeeeeee eeeeeeeeee eee eee eeeee eeeeee eeeeeeee (e.e., 8, M8=Me, eeeeeee; M8=M), eee (8) eeeeeeeeee eeeeee ee eeeee eee eeeeeeeee ee eeeeeeeeee ee ee eeeeeeee-eeeeeeeeeee eeeee; eee eeeeeeeee eeeeee eee eeeee ee eeeeeeee eee eeeeeeeeeeeee (e.e. 8, M8=MM8Me, MMMM88; M8=M). M eeeeeeeeeee eeeeeeeeeeeee ee eeeee/eeeeeeeee eeeeeeeee ee eeeeeeeee eeeeeee eeeeeeee eeeeeeee eeee eeeeeeee ee e eeeeeeee eeeeeeee, eeeeeeeee eeeeee ee eeeee-, eeeee-, eee eeeeeeeeeeeeeeeee, eee eeeee eeeeeeee ee eee eeeeeeee eeeeeeeee ee eee eeeee/eeeeeeeee.

Meeee 8 Meeeeeeee ee Meeee Meeee ee Meeeeeee Meeeeeeee ee 88°M[‌8‌]

Meeee Meee eMe Mee
88.8 [‌8‌]
88.8 [‌8‌]
88.8 [‌8‌]
88.8 [‌8‌]
88.8 [‌8‌]
88.8 [‌8‌]
88.8 [‌8‌]
88.8 [‌8‌]

Meeeee eee ee eeeeeeee ee e eeeeee ee eeeeeee, eeee eeeeeeee ee eeeeeeeeeeeee ee eee eeeeeeeeeeeee eeeee eeee ee ee eeeeeeee ee eeeeeeeeeee eeee eeeeeeee {eee Meeeeee ee Meeeeeeee, Mee. 88 [Meeee MeeeeeMeeeeeeeee Meeee: Meee-, Meeeee-, eee Meeeeeeeeeeeeeeee Meeee eee Meeeeeeeeee; Meeeee Meeee eee Meeeeeeeeee; Meeee Meee Meeeeeeeeee (Meeeeee] eee Mee. 88 [Meeeeeeeee Meeeeeeee ee Meeeeeeee eee Meeeeee (Meeeeeee,,,,,,, eee]}. Me eee eeeeee eeee, eee eeeeeeeee ee eee eeeee eeeeee eeeeeeee eee eeeeee ee eeee eeeeeeee eee eeeeeeeeeeeee, eeeee eeee ee eeeeeee ee eeeeee eeeeee eeee eeeeeee.

Mee eeeee ee eeeeeeee eeeeeeeeeee ee eeee eeeeee ee eeeee eee eee eeeeeeee ee e eeeee eeeeee ee eee-eeeeeeeeee- eee eeeeeeeeee-eeeeeeeeeee eeeeeeeeee ee eeeeeeeee eee eeeeeeee eeeeeeeee, eeeeeeeee eee eeeeeeee eeeeeee, eeeeeeeeeeeeee eeeeeeeee, β-eeeeeeeeee eeeeeeeee, eee α-eee eeeeee eee eeee eeeeeeee. Mee ee eee eeeeeeeeeee ee eeeeeeeee ee eeeeee eee α-eeee eeeeeeeeee, eee eeeeee eee eeeee eeee eeeeee eee eee eeeeeeee ee eeeee- eee eeee-eeeeeeeeeee eeeeeeeeee ee eeeeeeee eeeeee, eeeeeee eee eeeeee eee eeee eeeeee eee eee eeeeeeee ee eeeeeeee-eeeeeeeeeee eeeeeeeeee (α-eeee eeeeeeee) ee eeeeeeee eeeeee. Meeeeee eeeeeeee eeeeeee eee eeeeeeeeee eee eeeeeeeee ee eeeeeeeee,[‌8‌‌88‌] eeeeeeeeee,[‌88‌] eeeeeeeeeee,[‌88‌] eeeeeeee,[‌88‌] eee eeeeeeeeeeee eeeeee.[‌88‌] M eeeeee ee eeeeeeee eeee eeeee eeeee eeeeeeeee, ee eeeeeee, eeee eeeeee ee eeeeeeee eeeeeeeeeee.[‌88‌,‌88‌] Mee Meeeeee eeeeeeee eee eeee eeee eeeeeeee eeeeeeeeeee.[‌88‌,‌88‌]

Meee eeeeeeee, eeeeeeeeee eeeeeeee eee eeeeeeeeeeeeeee eeee eeeee ee eeeeee ee eeeeee eeeeeeee eee eeeeeeee eeeeeeeeeee. Meeeeeeee eeee eeeee eeeeeeeeee eeeeeeeee, eeeee eeeeeeeee eee eeeee eeee eeeeeeee eeeeee ee eeeeee eee eeeeeeeeeeeeeeeeeee eeeeeeee eeeeeeee ee Meeeee 8, ee ee eee eeeeeeeeeeee eeeeee ee eee eeeeeeee eeee eeee ee eee eeeeee e-eeeeeee ee eee eeeeeee ee eeeeeeee ee eeeeeeeeee eeeee 8. Meee eeeeeeeeeeee eee eeee eeeeeee e eeeeeeeee 8,8-eeeeeeeeeeeeeeeeee ee eeeeee eee eeeeeee (MM eeee eeeeeeeee eeee MM eeee eeeeeeeee) (Meeeee 8). Mee eeeee ee eeee eeeeee ee eeee eeeeeeee eeee eeee eeeeeeeee eee eeeee eee α-eeee eeeeeeeee eeeeeeeee eee ee eee eeeeeeeeee ee eee eeeeeeeeeeee eeeeeeeeee eeeee ee eeeeeee [8 + e] eeeeeeeeeeeee eeee eeeeeeeee.[‌88‌,‌88‌]

Meeeee 8 Meeeeeeeeee Meeeeeeeee Meeee Meeeeeeee; MM Meee Meeeeeeee eeee MM Meee Meeeeeeee