Enantioselective installation of adjacent tertiary benzylic stereocentres using lithiation–borylation–protodeboronation methodology. Application to the synthesis of bifluranol and fluorohexestrol

Abstract

Highly hindered benzylic carbamates have been reacted with hindered boronic esters to give tertiary boronic esters with very high diastereo- and enantiocontrol and the methodology has been applied to otherwise difficult-to-access molecules.

Towards the generalized iterative synthesis of small molecules

“…86 Amination followed by amide formation furnished the core of (+)-kalkitoxin in an overall 52% yield. This same approach has been used to synthesize baulamycin A, 87 tatanan A, 88 fluorohexestrol, 89 and C30 botryococcene 90 and many other targets. 91 More broadly, the versatility of this homologation method, which tolerates a diversity of structural variation in its building blocks, opens the door for divergent synthesis.…”

Structural Elucidation of the Mechanism of Molecular Recognition in Chiral Crystalline Sponges

“…Chemie propanol (1P2P) and 2-phenyl-1-propanol (2P1P) to investigate the chiral discrimination of our CMOM family towards their racemic mixtures.E nantiopure phenylpropanols are important intermediates used in the synthesis of pharmaceutical and parasiticide compounds. [16] Chiral resolution experiments were conducted using our previously reported procedure [5b] on activated CMOM crystals (see the Experimental Section in the Supporting Information for full details). The activated crystals were soaked in racemic mixtures of phenylpropanols for 5days before the crystalline solids were filtered and washed with cyclohexane to remove the excess of molecules adsorbed on the external surface.W et hen extracted the encapsulated phenylpropanols from the crystals using dichloromethane and we evaluated the enantioselective separation performance by analyzing the composition of the eluate through HPLC.…”

Lösungsmitteleinflüsse auf die Struktur und Stabilität von Alkalimetallcarbenoiden

“…B. in Cyclopropanierungen [7] oder Homologisierungsreaktionen. [8] Jedoch führt das gleichzeitige Vorhandensein von einem Metall und einer Abgangsgruppe zu einer inhärenten thermischen Labilität. Im Falle der Lithium-und Magnesiumcarbenoide finden Zersetzungsreaktionen durch Metallsalzeliminierungen häufig bei niedrigen Temperaturen statt, was eine kontrollierte Handhabung und Isolierung erschwert, sodass viele Transformationen immer noch mit in situ hergestellten Reagenzien durchgeführt werden.…”