A new type of C2-symmetric bisphospine ligands with a cyclobutane backbone: practical synthesis and application

Dongbo Zhao; Kuiling Ding

doi:10.1021/ol034299c

A new type of C2-symmetric bisphospine ligands with a cyclobutane backbone: practical synthesis and application

Org Lett. 2003 Apr 17;5(8):1349-51. doi: 10.1021/ol034299c.

Authors

Dongbo Zhao¹, Kuiling Ding

Affiliation

¹ State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, The People's Republic of China.

PMID: 12688756
DOI: 10.1021/ol034299c

Abstract

[reaction: see text] A highly efficient and practical optical resolution of anti-head-to-head racemic coumarin dimer, (+/-)-5, by molecular complexation with TADDOL (6) through hydrogen bonding and a convenient transformation of enantiopure 5 to a new type of C(2)-symmetric bisphosphine ligand (3) have been achieved. The asymmetric induction efficiency of these chiral bisphosphine ligands was evaluated in Pd-catalyzed asymmetric allylic substitution, affording the allylic substitution products in excellent yield (up to 99%) and enantioselectivity (up to 98.9% ee).