	US 7,589,218 B2
	Chiral spiro compounds and their use in asymmetric catalytic reactions
Xumu Zhang, State College, Pa. (US)
Assigned to The Penn State Research Foundation, University Park, Pa. (US)
Filed on Jul. 15, 2008, as Appl. No. 12/218,467.
Application 12/218467 is a division of application No. 11/218105, filed on Sep. 01, 2005.
Claims priority of provisional application 60/606556, filed on Sep. 02, 2004.
Prior Publication US 2008/0293953 A1, Nov. 27, 2008
Int. Cl. C07D 493/10 (2006.01)

U.S. Cl. 549—344 [549/220]

8 Claims

1. A process for the preparation of a spirobixanthenonediol ligand represented by the following formula:

or a ring-substituted derivative thereof, said process comprising the steps of:

contacting a compound represented by the following formula:

or a ring-substituted derivative thereof with n-BuLi and thereafter with a compound represented by the following formula:

wherein said contacting is carried out at a temperature and length of time sufficient to produce a xanthenol compound represented by the following formula:

or a ring-substituted derivative thereof;

contacting said xanthenol compound or a ring-substituted derivative thereof and a mixture of concentrated hydrochloric acid and acetic acid at a temperature and length of time sufficient to produce a dimethoxy spirobixanthene compound of the following formula:

or a ring-substituted derivative thereof; and

contacting said dimethoxy spirobixanthene compound or a ring-substituted derivative thereof and pyridine hydrochloride at a temperature and length of time sufficient to produce said spirobixanthenonediol compound.