A Stereoselective Approach to 1,3-Amino Alcohols Protected as Cyclic Carbamates: Kinetic vs. Thermodynamic Control

Abstract

Direct enantiocontrolled access to 1,3-amino alcohols protected as cyclic carbamates is described. The approach is based on the addition of a silyl dienolate to aldehydes in the presence of 10 % of Carreira's catalyst (vinylogous Mukaiyama-aldol addition). The obtained -hydroxyesters were reduced to pent-2-ene-1,5-diols, which were converted into the corresponding dicarbamates with tosyl isocyanate. Stereoselective cyclization of these dicarbamates proceeded with 1,3-asymmetric induction under either thermodynamic or kinetic control to afford enantioselectively six-membered-ring cyclic carbamates. Calculations enabled us to rationalize the observed stereoselectivity.