Readily available sulfamide-amine alcohols for enantioselective phenylacetylene addition to aldehydes in the absence of Ti(O(i)Pr)4.
نویسندگان
چکیده
Ephedrine-derived sulfamide-amine alcohol 3 was found to be an effective catalyst for the asymmetric phenylacetylene addition to aldehydes at room temperature without using Ti(O(i)Pr)4 and Zn(OTf)2. It afforded the propargylic alcohols in high yields (up to 99%) and good enantioselectivities (up to 84% ee), which were much higher than that based on N-methylephedrine under the same reaction conditions. Its weakly coordinative sulfonamide moiety of the ligand plays an important role for further acceleration and stereocontrol in the alkynylation.
منابع مشابه
Concise synthesis of novel practical sulfamide-amine alcohols for the enantioselective addition of diethylzinc to aldehydes.
Novel sulfamide-amine alcohol ligands were designed using a grafting strategy and synthesized from readily available starting materials via a simple, efficient method. The key features of these ligands for the asymmetric addition of diethylzinc to aldehydes included stability, enhanced effectiveness without using Ti(O(i)Pr)(4), suitability for a variety of aldehydes, the ability to operate at r...
متن کاملCamphor-based Schiff base ligand SBAIB: an enantioselective catalyst for addition of phenylacetylene to aldehydes.
A series of Schiff base ligands were synthesized from (1R)-camphor. Under the optimal conditions, (+)-SBAIB-a, 10 was found to be an excellent catalyst for the enantioselective addition of phenylacetylene to various aldehydes without utilizing either achiral additives or Ti(O(i)Pr)(4). This approach yielded (R)-propargylic alcohols in extremely high yields (up to 99%) and excellent enantioselec...
متن کاملAsymmetric Functional Organozinc Additions to Aldehydes Catalyzed by 1,1′-Bi-2-naphthols (BINOLs)†
Chiral alcohols are ubiquitous in organic structures. One efficient method to generate chiral alcohols is the catalytic asymmetric addition of a carbon nucleophile to a carbonyl compound since this process produces a C-C bond and a chiral center simultaneously. In comparison with the carbon nucleophiles such as an organolithium or a Grignard reagent, an organozinc reagent possesses the advantag...
متن کاملA Lewis acid activated reaction of Zn with EtI to promote highly enantioselective alkyne additions to aldehydes.
An easily available BINOL-Ti(O(i)Pr)4 catalyst system is found to activate the reaction of Zn powder with EtI for the asymmetric alkyne addition to aldehydes at room temperature. It allows the synthesis of a number of synthetically useful chiral propargylic alcohols with both high yields and high enantioselectivity (up to >96% ee).
متن کاملAziridine sulfides and disulfides as catalysts for the enantioselective addition of diethylzinc to aldehydes.
Chiral aziridine sulfides and disulfides were synthesized from readily available and inexpensive R-cysteine by a Mitsunobu reaction; their application in the addition of diethylzinc to aldehydes provides secondary alcohols with up to 99% ee and S-configuration.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Chirality
دوره 17 5 شماره
صفحات -
تاریخ انتشار 2005