. Author manuscript; available in PMC: 2008 Dec 5.

Published in final edited form as: J Org Chem. 2007 Feb 2;72(3):756–759. doi: 10.1021/jo061339s

Table 2.

Results of reaction between β-lactams 5a–e, 6 and 7-O-triethylsilylbaccatin III (7, Scheme 3) for the formation of 8 (entries 1–3) and 9 (entries 4–6).

Entry	R¹	R²	Yield (%)^a	Isomeric ratio^b
1	TIPS	Ph	80	32 : 1
2^c	TBS	Ph	81	41 : 1
3	TES	Ph	84	10 : 1
4	TIPS	tert-butyl	76	57 : 1
5	TBS	tert-butyl	84	82 : 1
6	TES	tert-butyl	78	40 : 1

Yields of 8 (entries 1–3), and of 9 (entries 4–6) for two steps; ;

The isomeric ratio (2′R,3′S) : (2′S,3′R) was determined by HPLC;

Same as entry 1, Table 1.