Enantioselective intramolecular [2+2+2] cycloaddition of triynes for the synthesis of atropisomeric chiral ortho-diarylbenzene derivatives

An iridium-chiral diphosphine complex was used to catalyze an enantioselective [2+2+2] cycloaddition of oxygen- and nitrogen-bridged triynes with ortho-substituted aryl groups on their termini. ortho-Diarylbenzenes with atropisomeric chiralities were obtained in high yield and enantiomeric excess.

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(−)-4,5-Di(napthalen-1-yl)-1,3,6,8-tetrahydro-2,7-dioxaas-indaceneC30H22O2Ee = 90%[α]D29=-347.9 (c 1.7, CHCl3)Source of chirality: (S,S)-MeDUPHOSAbsolute configuration: not determined

(−)-4,5-Di(anthracen-1-yl)-1,3,6,8-tetrahydro-2,7-dioxaas-indaceneC38H26O2Ee = 87%[α]D23=-604.3 (c 0.19, CHCl3)Source of chirality: (S,S)-MeDUPHOSAbsolute configuration: not determined

(−)-4,5-Di(phenanthren-9-yl)-1,3,6,8-tetrahydro-2,7-dioxaas-indaceneC38H26O2Ee = 87%[α]D23=-120.6 (c 0.79, CHCl3)Source of chirality: (S,S)-MeDUPHOSAbsolute configuration: not determined

(−)-4,5-Bis(4-methoxynaphthalen-1-yl)-1,3,6,8-tetrahydro-2,7-dioxaas-indaceneC32H26O4Ee = 90%[α]D24=-282.8 (c 1.8, CHCl3)Source of chirality: (S,S)-MeDUPHOSAbsolute configuration: not determined

(−)-4,5-Bis(4-methoxy-2-methylphenyl)-1,3,6,8-tetrahydro-2,7-dioxaas-indaceneC26H26O4Ee = 95%[α]D21=-31.6 (c 0.61, CHCl3)Source of chirality: (S,S)-MeDUPHOSAbsolute configuration: not determined

(−)-4,5-Bis(2-chloro-4-nitrophenyl)-1,3,6,8-tetrahydro-2,7-dioxaas-indaceneC22H14Cl2N2O6Ee = 90%[α]D21=-116.9 (c 1.8, CHCl3)Source of chirality: (S,S)-MeDUPHOSAbsolute configuration: (S,S)

(−)-4,5-Bis(4-methoxynaphthalen-1-yl)-2,7-bis(p-toluenesulfonyl)-1,3,6,8-tetrahydro-2,7-diazaas-indaceneC46H40N2O6S2Ee = ca. 95%[α]D21=-258.8 (c 0.54, CHCl3)Source of chirality: (S,S)-MeDUPHOSAbsolute configuration: not determined