Navigation

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
1.1.1.3 Secondary Cycle Catalysis

DOI: 10.1055/sos-SD-201-00002

Muñiz, K.Science of Synthesis: Stereoselective Synthesis, (2011126.

In the area of catalytic dihydroxylation, Sharpless coined the term secondary cycle (see Scheme 6).[‌72‌] Originally, this was an unwanted reaction path since it was shown that the chiral cinchona alkaloid ligand does not participate in this catalytic diol formation and thus dihydroxylation by this sequence is deprived of ligand-acceleration effects. Therefore, products with very low or no enantiomeric excess result as a direct consequence of slow diol hydrolysis of the initially formed osmium(VI) glycol ester 8, which, under catalytic conditions, undergoes fast reoxidation to the corresponding osmium(VIII) glycol ester 9 and thereby enables a second dihydroxylation via bis(glycolate) 10 to furnish the bis(glycolate) 11, which represents the resting state of the catalyst and significantly diminishes the overall rate (Scheme 18).

Meeeee 88 Mee Meeeeee ee Meeeeeeee Meeee Meeeeeeee[‌88‌,‌88‌]

Meeeeee eeeeeee ee eeeeeee eeeeeee eeeee eeeeeeeeeeeeeee eeee ee eeeeee eee eeeeeeeeeeee eeee eeeee ee eeeeeeeee eeeeeeeeee eeeeeeeeee ee eeee eeeee eeeeeeeee eeeeeeee eeeeee eeeeeeeeeee eeeeee eee eeeeee eeeee.[‌88‌] Meeeeeeeee, eee eeee-eeeeeeee eeee, eee eeeeeeeeee ee eee eeeeee eee(eeeeeeeee), ee eeeeeeeeeeeee eeeeeeee ee eee eeeeeeee ee eeeee eeeee eeeeeeeeee eeeeee, eeeee eeeee eeeeeeeeee eeeee eeee eeee eee eeee eeeeeeeeee eeee. Mee eeeeeee ee eeeeeeeee ee e eeeee eeeeeeee ee eeeeee(MMMM) eeeee eee eee eeeeeeeee eeeeee ee eeee ee eeeeee(MM) eeeeeeeee. Meeee eee eeeeeeee ee eeeeeeeee eeeee eeee eeeeee(MM)eeeee eee eeee eeee eeeeeeee ee eeee eeeee eeeeeeeeeeeeee ee ee eeeeeeeeeee eeeeeeee, eeeeeeeeee ee eee eeeeeeeee eeeee ee eeeeeeee ee eeeeeeee eeeeeee ee eee eeeeee eeeeeeeee eeeeee(MM) eeee eeeeee eeee ee eeeeeeee. M eeeeeeeee ee Meeeeeeee eeeeeeee eeee e eeeeeee ee eeeee eeee eeeeeeeeee eeeeee ee eee eeeeeeeee eee eeee eee eeeeeee eM eeeee ee 88 (Meeee 8; ee eeeee eeeeeeeee, ee eeeeee eeeeee ee eeeeeeee, ee eeeeeeee 88 eee eeeeeee).[‌88‌] Meeeeee eeeeeeeeee eeeeeeeeee eee eeeeeeee ee eeeeee ee eeee eM eeeee: 8-eeeeeeeeeeeeeeee, eeeeee eeee eee eeeeeeee eeeeeee 8-eeeeeeeeeeeeeeee M-eeeee, ee eeeeeeeeeee, eee eee eeeeeeeee ee e eeeeeeeeeeeee eeeee eeeeeeeeeee eeeeeee ee eeeeeeeee. Meeee eee eeee eeeee eeee eeee eeeeeeee, eeeeee eeee eeeee ee eeeeeeeeeeeee eeeeee eeeeeeee, eeee eeeeeeee eee ee eeeeeeeee ee e eeeeeeee eeeeee(MMMM) eeeeeee 88 (Meeeee 88) eeee eeeeeeee eeeeeeee eeeeeeeeeeeee eeee eeeeeeeeeeeeeeeeee. Meeeeeee, eeeeeeeeeeeee ee eee eeeeeeee eeee eeeeeeee eeeeee ee eeeeeeeeeee eeeeeee eeeeeee ee eeee eeeeeeeee.

Meeeeee, eee eeeeeeeeeee ee eeeeeeee eeeeeee ee eeeee eeeeeee. Meeeee eee ee eee eeeeee eeeeeee eeeeeeee ee eeeeeeee ee eeeeee, Meñee eeeeeee e eeeeee ee eeeee eee eee ee eeee eeeeeeeee ee ee eeeeeeeeeeeeeeeee eeee ee eeeeee eeeeeee eeeeee eeeeeeeeeeee. Mee eeeeee eeeeee(MMMM) eeeeeee 88 ee eeeeee ee eeee eeee M,M-eee(eeeee)-8,8-eeeeeeeeeeeeeee eeee eee eeeeeee eeeeee eeeeeee eeee ee eeeeee(MMM) eeeeeeee, eeeeeeeee eeeeee(MM), eee eeeeee(MMMM) eeeee. Meeeeeeee eeee 8-eeeeeeeeeeeeeeee M-eeeee ee eeeeeeeee eeeee ee eeeee eeee eeeeeeeee eeee eeeeeee eeee ee 8,8-eeeeeeeeeeeeee (eeeeeeee), eeeeeeeeeeeeeeeeee eee eeeeeeee eeeeee eeee eeeeee eeeeeee eeee 88 ee 88%.[‌88‌]

Meeeee 88 Meeeeeee Meeeee Meeeeeeee eee Meeeeeeee Meeee Meeeeeeee[‌88‌,‌88‌]

Meeee 8 Meeeeeeeeeeeeee ee Meeeeee eeeee Meeeeeeee Meeee Meeeeeeeee[‌88‌]

Meeeeeee Meeeeeee Meeeeee Meeee (%) Mee
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]
88 [‌88‌]

Meeeee eeeeeeeeee eeeeeeee eeeeeeeee eeee eeeeeeeee ee eeeeeeeee eee eeeeeee eeee ee eeeeeee eeeeeeeeeee eeee e eeeeee eeeeee eeee ee eeeeeeee eeee. Meeee eeee eeeeee eeee eeeeeeeeee eeeeee eeeeeeee, eeeeee ee eeeeeee ee eeeee 88eee%, eee eeeeeee M-eeeee β-eeeeeee α-eeeee eeeee 88 eee 88 eeeeeeeee eeeeee ee ee eee eeeeeee ee eeeeee eee eee eeeeeeeeeeeeeee ee eeeeeee 88 ee eeee eeeee 88 (Meeeee 88).[‌88‌]

Meeeee 88 Meeeeeeeeeeeeeee Meeeeeeeeeeeeee ee Meeeeee eeeee Meeeeeeee Meeee Meeeeeeeee[‌88‌]

Meeeeeeeeee 88

Me8 M8 Meeeee Meeeee (%) ee (%) Meeeee Mee
Me Me 88 e.e 88 8M,8M [‌88‌]
Me Me 88 e.e. 88 8M,8M [‌88‌]
Me eMe 88 e.e. 88 8M,8M [‌88‌]
8-M8MM8M8 Me 88 88 88 8M,8M [‌88‌]

e e.e.=eee eeeeeeee.

Meeeeeeeeeee Meeeeeeee

Meeee 88; Meeeeee Meeeeeeee eee Meeeeeeeeeeeeee eeeee Meeeeeeee Meeee Meeeeeeeee:[‌88‌]

MMMMMMM: Meeeeeeee eeeeee(MM) ee eeeeee eeeee.

Mee eeeeee 88 (8.8eee) eee eeeeeeeee ee e eeee ee eeeeee eeee (88.8e, 8.8eee) ee eeeeeee ee e-MeMM/M8M (8:8; 888eM) ee e 888-eM Meeeeeeeee eeeee. M8[MeM8(MM)8] (8.888e, 8.8eee%) eee eeee eeeee, eeeeeeee ee MMM (88ee% eeee ee M8M, eeeeeeee eeee Meeeeee; 88.8eM, 8.88eee). Mee eeeeeee eeeeee eeeeee eeeee eee eee eeeeeee ee ee eee 88e, eeeee eeeee ee eeeeee eeeeee eeeeeeeee. Mee eeeeeeeeeee eee eeee eeeeeeeee ee eeeeeeeeee, eeeeee eeee 8M MMe (888eM) eee M8M, eee eeeee ee eeeeee eee eeee eeee eeeeeee ee e eeeee eeeee.

Meeeee (8M,8M)-8,8-Meeeeeeee-8-(8-eeeeeeeeeee)eeeeeeeeee (88, Me8=8-M8MM8M8; M8=Me); Meeeeee Meeeeeeee:[‌88‌]

MMMMMMM: Meeeeeee ee eeeeee(MMMM) eeeee eee eeeeee ee eeeee eeeeeeeeeeeeee, eee eeeeeeeeee eeee eeeeeee eeee eeeeeeeee.

(M)-Meeeee 8-(8-eeeeeeeeeee)eeeeeeee (88, Me8=8-M8MM8M8; M8=Me; 8.88e, 88eeee) eee M-eeeee-e-eeeeeeeee (88; 888ee, 8eee%) eeee eeeeeeeee ee e-MeMM/M8M (8:8; 88eM). MMM (88ee% ee M8M; 8.88eM, 88eeee) eee 8.8M MeM8 ee MeMM (888µM, 8.88eeee) eeee eeeee eeeeeeeeeeee. Mee eM eee eeeeeeee ee 8 ee eeeeeeee ee 8M M8MM8 (8.8eM), eee eee eeeeeee eee eeeeeee eeeeeeeeee eee 88e, ee eeeee eeeee eee eM eee eeeeeeee ee 8 eeeee. Meeee ee eeeeeeeeee 88e, eee eeeeeee eee eeeeeeee ee e eeeee eeeee; eeeee: 8.8e (88%); 88% ee.

References


Cookie-Einstellungen