Heterohelicenes with Embedded P-Chiral 1<i>H</i>-Phosphindole or Dibenzophosphole Units: Diastereoselective Photochemical Synthesis and Structural Characterization
dibenzophosphole substituents have been applied to the synthesis of P/N‐bi‐heterosubstituted dimeric helicenes, as well as of new [6]‐ and [8]phosphahelicenes. In these photocyclization processes, the configuration of the stereogenic phosphorus center dictates the sense of helical chirality. Thus, by starting from enantiomerically pure P‐menthylphosphole‐oxide units, this method affords enantiopure helical compounds
transition‐metal catalysis. Unlike all known helical phosphines used so far in catalysis, the phosphorus function of phosphahelicenes is embedded in the helical structure itself. This crucial structural feature originates unprecedented catalytic behaviors and efficiency. An appropriate design and fine tuning allowed both high catalytic activity and good enantiomeric excesses to be attained in the gold promoted
Phosphahelicenes with (Thio)Phosphinic Acid and Ester Functions by the Oxidative Photocyclisation Approach
作者:Julie Febvay、Charles S. Demmer、Pascal Retailleau、Jeanne Crassous、Laura Abella、Jochen Autschbach、Arnaud Voituriez、Angela Marinetti
DOI:10.1002/chem.201903750
日期:2019.12.5
with thiophosphinic acid and ester functions have been obtained by the oxidative photocyclisation of olefins bearing both a benzophenanthrene and a benzophosphole unit. When the method has been extended to olefins bearing a partially saturated benzophospholene unit, a divergent regioselectivity of the photocyclisation step has been observed, leading to new helicenes in which the phosphorus function