Table 1.

Mb(H64V,V68A)-catalyzed cyclopropanation of p-chlorostyrene with ex situ generated diazoacetonitrile.^[a]

Entry	Cat.	OD600	equiv 1[b]	Conv. (Yield)[c]	TON	% de	% ee
1	protein	-	5	0	-	-	-
2	cells	80	5	44%	230	99.9	99.9
3	cells	40	5	43%	465	99.9	99.9
4	cells	20	5	55%	930	99.9	99.9
5	cells	10	5	50%	1,700	99.9	99.9
6	cells	5	5	46%	3,110	99.9	99.9
7[d]	cells	20	10	40%	675	99.9	99.9
8[e]	cells	20	5	72% 87%[f]	1,500	99.9	99.9
9[e,g]	cells	20	5	86%[f] (81%)[f]	5,600	99.9	99.9

^[a]Reaction conditions: 10 mM 4-chloro-styrene (2a), purified Mb variant (20 μM) or Mb(H64V,V68A)-expressing E. coli (BL21(DE3)) cells in KPi 50 mM (pH 7), at 20 mL-scale, RT, 5 hours. NaNO₂ was slowly added over 30 min.^[22]

^[b]Relative to olefin.

^[c]Product conversion as determined by SFC. Isolated yields are reported in brackets. Errors are within 10%.

^[d]Slow addition of NaNO₂ over 4h.

^[e]2-Aminoacetonitrile in 2 mL of 1:1 H₂O:toluene mixture.

^[f]Reaction time: 15 hours.

^[g]2a at 30 mM.