Synthesis of (–)-Indolizidine 167B based on domino hydroformylation/cyclization reactions

• Giuditta Guazzelli,
• Raffaello Lazzaroni and
• Roberta Settambolo

Beilstein J. Org. Chem. 2008, 4, No. 2, doi:10.1186/1860-5397-4-2

• conversions, practically the same ee, that is, the starting ee value (92%). A similar behaviour occurred for dihydroindolizine 3, its ee value remaining the same as that of the corresponding olefin 1 (ee 92%) at all reaction times. The isomerization of b into l and the absence of racemization of starting

Large- scale ruthenium- and enzyme- catalyzed dynamic kinetic resolution of (rac)-1-phenylethanol

• Krisztián Bogár,
• Belén Martín-Matute and
• Jan-E. Bäckvall

Beilstein J. Org. Chem. 2007, 3, No. 50, doi:10.1186/1860-5397-3-50

• racemization of 1-phenylethanol (2) in the presence of the immobilized enzyme, and could be used in 0.05 mol% with high efficiency. Commercially available isopropenyl acetate was employed as acylating agent in the lipase-catalyzed transesterifications, which makes the purification of the product very easy. In

• ][28] and recently this approach has been extended to dynamic kinetic resolution (DKR) by combining the enzymatic resolution with a metal-catalyzed racemization. [29][30][31][32][33][34][35][36][37] Today, many stable lipases are commercially available and they are frequently used in synthetic organic

• "in situ" racemization of the substrate using a ruthenium(II) racemization catalyst (1) at ambient temperature (Figure 1).[32][34] Many 1-arylethanols are used as intermediates for the synthesis of pharmaceuticals and agrochemicals,[40][41] and they are therefore needed in enantiomerically pure form