Efficient Oxidative Resolution of 1-Phenylphosphol-2-Ene and Diels–Alder Synthesis of Enantiopure Bicyclic and Tricyclic P-Stereogenic C-P Heterocycles

K. Michał Pietrusiewicz,Renata Parcheta,Zbigniew Drzazga,Iwona Justyniak,Elżbieta Łastawiecka,Marek Koprowski,Oleg M. Demchuk

doi:10.3390/sym12030346

Abstract

1-Phenylphosphol-2-ene 1-oxide is effectively resolved by L-menthyl bromoacetate to afford both SP and RP enantiomers of 1-phenylphosphol-2-ene 1-oxide on a multigram scale. The resolved 1-phenylphosphol-2-ene oxide has been found to undergo face-selective and endo-selective cycloadditions with a series of acyclic and cyclic dienes to produce enantiopure P-stereogenic C-P heterocycles of hexahydrophosphindole and hexahydrobenzophosphindole as well as phospha[5.2.1.02,6]decene and phospha[5.2.2.02,6]undecene structures. Conversions of these cycloadducts to the fully saturated heterocyclic systems as well as to their P (III), P = S, P = Se and P-BH3 derivatives have been demonstrated to occur with retention of configuration and preservation of configurational homogeneity at P. A perplexing case of stereomutation at P during reduction of a tricyclic β-hydroxy phosphine oxide by PhSiH3 at 80 °C has been recorded.

Highlights

Active P-stereogenic organophosphorus compounds are of great importance in organic synthesis [1,2,3,4]
Racemic 1 was synthesized from butadiene and P,P-dichlorophenylphosphine via intermediate cyclic
Racemic 1 was synthesized from butadiene and P,P-dichlorophenylphosphine via intermediate chlorophosphonium chloride (a 1,4-cycloadduct) which after a hydrolytic work-up afforded rac-1 in cyclic chlorophosphonium chloride (a 1,4-cycloadduct) which after a hydrolytic work-up afforded good yield (Scheme 1)

Summary

Introduction

Active P-stereogenic organophosphorus compounds are of great importance in organic synthesis [1,2,3,4]. Despite many developed asymmetric syntheses [1,7,8,9,10,11,12,13,14,15,16,17,18], desymmetrizations [14,19,20,21,22,23,24,25,26,27] and kinetic resolutions [28,29,30,31,32,33,34], practical preparations of optically active P-stereogenic compounds are still relying in great part on classical resolution of racemates [7,8,35,36,37,38,39,40] The latter has the advantage to rely on cheap and often recoverable chiral auxiliaries, uses crystallization for separation of the P-epimers and, Symmetry 2020, 12, 346; doi:10.3390/sym12030346 www.mdpi.com/journal/symmetry by avoiding chromatography, usually secures convenient access to resolved P-stereogenic compounds in multigram quantities [41].[41]. Our studies, wefound havethat found thatsynthetically several synthetically useful Pcompounds compounds could be readily resolved into enantiomers by the use of L-menthyl as the stereogenic could be readily resolved into enantiomers by the bromoacetate use of L-menthyl chiral auxiliaryas[38,39,42,43].

Methods

Results

Conclusion