Computationally Aided Absolute Stereochemical Determination of Enantioenriched Amines

A simple and efficient protocol for sensing the absolute stereochemistry and enantiomeric excess of chiral monoamines is reported. Preparation of the sample requires a single-step reaction of the 1,1′-(bromomethylene)­dinaphthalene (BDN) with the chiral amine. Analysis of the exciton coupled circular dichroism generated from the BDN-derivatized chiral amine sample, along with comparison to conformational analysis performed computationally, yields the absolute stereochemistry of the parent chiral monoamine

Mechanistically Inspired Route toward Hexahydro‑2<i>H</i>‑chromenes via Consecutive [4 + 2] Cycloadditions

Utilizing two robust C–C bond-forming reactions, the Baylis–Hillman reaction and the Diels–Alder reaction, we report a highly enantio-, regio-, and diastereoselective synthesis of hexahydro-2<i>H</i>-chromenes via two sequential [4 + 2] cycloadditions. These tandem and formal cycloadditions have also been performed as a “one-pot” sequence to access the corresponding heterocycles constituting up to five contiguous stereocenters in excellent yields and stereoselectivity