Enantioselective Synthesis of Cyclopropylphosphonates Containing Quaternary Stereocenters Using a D₂-Symmetric Chiral Catalyst Rh₂(S-biTISP)₂

Abstract

[reaction: see text] Rh(2)(S-biTISP)(2)-catalyzed reactions of dimethyl aryldiazomethylphosphonates generate donor/acceptor-substituted rhodium carbenoid intermediates capable of cyclopropanation of styrenes in high yields (85-96%), diastereoselectivity (> or =98% de), and enantioselectivity (76-92% ee).

Rh2(S‐1,2‐NTTL)4: A Novel Rh2(S‐PTTL)4 Analog With Lower Ligand Symmetry for Asymmetric Synthesis of Chiral Cyclopropylphosphonates

“…(1S,2R)-Diethyl 1,2-diphenylcyclopropylphosphonate (10) 55 . (1S,2R)-Diethyl 1,2-diphenylcyclopropylphosphonate (10) 55 .…”

“…1S,2R)-Dimethyl 1,2-diphenylcyclopropylphosphonate (5)54,55 . Colorless oil; R f = 0.15 (1:1 ethyl acetate: n-hexane); Enantiomer separation by HPLC (Chiralcel OJ column, 25 x 0.46 cm, 2% 2-propanol in n-hexane (v/v%); 1 mL/min, 220 nm, τ 1 = 18 min, τ 2 = 21 min).…”

Organophosphorus Chemistry

“…47 The oxathiaphospholane methodology has been applied to the synthesis of N-phosphorothioylated amino acids as well as O-phosphorothioylated derivatives of hydroxyamino acids, i.e., serine, threonine and tyrosine. 55 Organophosphorus and nitro-substituted sulfonate esters of 1-hydroxy-7-azabenzotriazole (96), (97) and (98) Chemical transformation of Leustroducsin H (99) to Leustroducsin B (100) having various biological activities has been successfully accomplished in 11 steps including enzymatic hydrolysis of phosphate ester ( Figure 21). Compounds (86) were converted into the corresponding methyl or benzyl phosphorothioamides (89) by DBU-assisted treatment with methyl or benzyl alcohol.…”

“…Similar transformations using diphenylphosphine oxide and diethyl thiophosphite have also been performed. 99 new water-soluble calix[4]-arene-based bipyridyl podand (194) has been elaborated by incorporation at the upper rim of four phosphonate groups. The latter are capable of cyclopropanation of various styrene derivatives affording cyclopropylphosphonates (193) in high yields (85-96%), diastereoselectivity (>98% de), and enantioselectivity (76-92% ee) ( Scheme 52).…”

Studies of the Synthesis of Diethyl Cyclopropylphosphonate and Its Thio and Seleno Analogs

“…[8] Hence, continuous effort has been made to find simple new routes for the synthesis of cyclopropylphosphonates. Various methods have been reported, such as phosphonylation of halogenated cyclopropanes, [9] decomposition of diazophosphonates, [10,11] cyclopropanation of vinylphosphonates, [12 -15] electrochemical methods, [16 -18] addition of phosphates to imminium salts, [19] fragmentation and rearrangement of epoxyethylphosphates, [20] alkylation of benzylphosphonate carbanions with 1,2-dibromoethane, [21] addition of fumarates to phosphonylated sulphonium ylides, [22] Michael-induced ringclosure reactions, [23] and enantioselective synthesis using a D 2 -symmetric chiral catalyst Rh 2 (S-biTISP) 2 [24] or chiral ruthenium porphyrins. [25] However, in most cases, these syntheses were performed via an appropriate phosphonate as starting material, which eventually led to ring-substituted cyclopropylphosphonates.…”