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.
6.1.28.24.1.2.5 Variation 5: Copper-Catalyzed Addition of Diboron Reagents to Alkynes

DOI: 10.1055/sos-SD-106-00088

Vaultier, M.; Pucheault, M.Science of Synthesis Knowledge Updates, (20124308.

Nucleophilic borylcopper species, prepared by treating bis(pinacolato)diboron with copper(I) chloride and potassium acetate in dimethylformamide, undergo addition to alkynes to give the corresponding alkenylboronates.[‌20‌] This method can be extended to provide an efficient synthesis of β-borylated α,β-alkenic esters 32 from α,β-acetylenic esters 31 by using a copper–phosphine catalyst based on ligand 30 (Xantphos) (Scheme 13).[‌21‌] The product of syn-addition to the triple bond is obtained almost exclusively, except in the case of the β-tert-butyl-substituted ester 31 (R1 = t-Bu).

Meeeee 88 Meeeee-Meeeeeeee Meeeeeee ee Meeeeeeeee Meeeee[‌88‌]

Meeeeeeeeee 88

M8 Meeee (%) Meeeee Mee
(MM8)8Me 88 M [‌88‌]
Me 88 M [‌88‌]
MM8Me 88 M [‌88‌]
e-Me 88 M/M (88:88) [‌88‌]
M 88 M [‌88‌]

Meeeeeeeeeeeeee, eee β-eeeeeeee ee α,β-eeeeeeeeee eeeee 88 eeeeee eeeeeee eeeeeeeee eeeeeeee ee e eeeeeeeee-eeeeeee eeeeeeeeeee eeeeeee 88 ee eee eeeee, eeeeeee ee ee eeeeeeeeeeee eeeeeeeeeeee eeeeeee 88 (Meeeee 88). Meeee eeeeeeeeeee eeee eeeeeeee, 88 eeeeee eee eeeeeee eeeeeeee 88 eee e eeeeee eeeeeeee; eee eeeeee eeeeee eeee eee(eeeeeeeeee)eeeeeeee ee eeeeeeeeee eee eeeeee eeeeeeee 88.[‌88‌]

Meeeee 88 Meeeeeee Meeeeeeee Meeee eee eee Meeeee-Meeeeeeee Meeeeeee ee Meeeeeeeee Meeeee[‌88‌]

Meeeee eeeeeeee eeeeeee eeeeeee eeeeeeeeeeeeeeee-8-eeeeee eeeeee eeeeeee eeeeee eeeee- eee eeeeeeeeeeeeeee eeeeeeee ee eeeee ee eeeeeeee eeeeeee ee eeee eee eeeeeeeeeeeee eeeeeeeeeeeeeeee.[‌88‌] Meee eeeeeeee ee eeeeeeeee ee eeeeee eeeeeee ee eeeee eeeeee eee eeeeeeeeee eeeeeee ee eeee eeeeee. Mee eeeeeeee eee ee eeeeeeee ee eeeeeeeeeee eeee eeeee eeeeee eeee eee eeeeeeeeeeeeeeee-8-eeeeee ee eeeeeee eee eeeeeeeeee. Mee eeeeeeeee eeeeeeeeee ee eee eeeeee eeeeeeeee eee ee eeeeeeee eeeeeeee ee eeeee ee eeeeeeee-eeeeeeee eeeeeeeeeee eeeeeeeee eeeeee eeee ee eee-8-eeeeeeeeeeeeee. Meeeee ee eee eeeeeeeeeeeee eeeeeeee 88M eee 88M eee eeeeeeeee, eeeeee eeee eeeee eeeee eeeeee eee eeeeeee ee eee eeeeee (Meeeee 88).[‌88‌]

Meeeee 88 Meeeee-Meeeeeeee Meeee Meeeeeee ee Meeeeee[‌88‌]

Meeeeeeeeee 88

M8 M8 Meeee (%) Meeee (88M/88M) Mee
Me 8-MM8M8 88 8:888 [‌88‌]
Me 8-MMM8M8 88 8:888 [‌88‌]
Me 8-eeeeeeee 88 8:888 [‌88‌]
Me eeeeeeeeee-8-ee 88 8:888 [‌88‌]
Me Me 88 88:88 [‌88‌]
Me 8-eeeeeee 88 8:888 [‌88‌]
Me 8-eeeeeee 88 8:888 [‌88‌]
e-Me 8-MeMM8M8 88 888:8 [‌88‌]
e-Me (MM8)8Me 88 888:8 [‌88‌]

Meee eee eeeeeeeeee eeeeeeeee eeee-eeeee-eeeeeeeeeee eeeeeee, eee eeeeeeee eeeeeeee eeeeee eeeeee, eeeeeeee ee e eeeeee ee eeeeee eee eeeeeeeeee eeeeeee, eee eeee eeeeeeeee eeee ee ee ee eeeeeeeeee. Me ee eeeeeeeeee eeee ee eeeee eeeee eee eeeeeee ee eeeeeeee ee eee eeeeee eeeeee 88M.

References