2 Shown Below Is The Reaction Scheme For An Aldol Addition Controlled With A Chiral Auxiliary Oh Auxiliary Me Opmb Aux 1 (44.6 KiB) Viewed 100 times
2 Shown Below Is The Reaction Scheme For An Aldol Addition Controlled With A Chiral Auxiliary Oh Auxiliary Me Opmb Aux 2 (26.87 KiB) Viewed 100 times
2 Shown Below Is The Reaction Scheme For An Aldol Addition Controlled With A Chiral Auxiliary Oh Auxiliary Me Opmb Aux 3 (26.87 KiB) Viewed 100 times
2. Shown below is the reaction scheme for an Aldol addition controlled with a chiral auxiliary. OH Auxiliary Me OPMB Auxiliary Bu BOTT, IP NET aqueous workup Me OPMB a) Assign (R/S) configuration for the stereocenters in the product. OH Auxiliary Me OPMB b) The reaction proceeds with <1:500 selectivity for the stereochemistry designated by the red stars. Is this reaction stereoselective, stereospecific or enantioselective? c) Attacking which face of the aldehyde (Re or Si) will lead to the assigned product?
d) Propose a mechanism that takes you from starting materials to products. Protonated iPr2NEt has a pka of 11.1. Don't worry about the Boron reagent. It is used to control the overall stereochemistry of the reaction, but the exact process will be discussed later in the course. Hint: This mechanism has shown up before as a part of a problem in this class!
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